1. Introduction
The rise of the non-state armed group and the terrorist organisation known as Daesh is a serious challenge to international law. Among other challenges, the terrorist attacks of November 2015 in Paris were considered by the French president at the time, François Hollande, as an ‘act of war’.Footnote 1 The intense violence exercised by the members of this terrorist group, their level of organisation and their occupation of broad territories in countries such as Iraq, Syria and the Philippines can easily justify the inclusion of their activities under the status of armed conflict.Footnote 2 This situation has raised many concerns in the scholarship in relation to one of the traditional branches of international law: the right of self-defence and the prohibition of use of force.Footnote 3
However, the use of military force cannot be the only response to the threat of terrorist organisations such as Daesh. Military power must be combined with other responses, including the ‘legitimate use of violence’ represented by criminal law.Footnote 4 The United Nations Security Council (UNSC) recognises that military force must be complemented with law enforcement measures and intelligence cooperation, especially after the increasing security threat posed by the high number of nationals from Western countries who have joined the ranks of Daesh and other terrorist groups in the Middle East and North Africa.Footnote 5
Although foreign fighters are not a new phenomenon,Footnote 6 the rise of Daesh has resulted in a turning point in the evolution of their numbers, origins, motivations and methods.Footnote 7 Currently, Daesh has lost nearly all the territories it once held. The current problem is what to do with the ‘diaspora’ of foreign fighters.Footnote 8 The defeat of Daesh has left in countries such as Syria and Iraq many individuals whose prosecution depends on effective criminal cooperation between several states, as well many others who have managed to return to their countries of origin after participating in conflicts abroad.Footnote 9
The President of the United States has urged the countries of origin, mainly European states, to take all necessary measures to guarantee the extradition and prosecution of their own nationals.Footnote 10 On the one hand, countries such as the United States, Russia, Indonesia and Kazakhstan have been in favour of the detention and extradition of their nationals.Footnote 11 On the other hand, Canada, the United Kingdom and most European countries do not have a clear position on whether they will accept their nationals for prosecution and the legal procedures they would apply in such cases.Footnote 12 The question is, essentially, what is the legal basis for their detention, prosecution and extradition.Footnote 13 In other words, what is the legal basis for bringing terrorists to justice in the context of armed conflict?
The domestic legal orders of the countries in which the armed conflict takes place do not typically offer a definitive response to this question and, when they do, such response usually relies on the international instruments ratified by that state. According to the reports prepared by the Middle East and North Africa Financial Action Task Force (MENAFATF), both Iraqi and Syrian laws, for instance, establish that extradition and mutual legal assistance are governed by bilateral and multilateral treaties and it is only when such treaties are non-existent or not applicable that cooperation may be provided on the basis of reciprocity.Footnote 14 The United States, for example, has recently relied on the Convention on the Prevention and Punishment of Crimes Against Internationally Protected PersonsFootnote 15 for the extradition of a suspect who allegedly killed a US diplomat during the armed conflict in Mali.Footnote 16
However, as we shall see in more detail in this study,Footnote 17 there is great confusion about the application of the UN conventions against terrorism to scenarios of armed conflict. The United Nations Office on Drugs and Crime (UNODC), in its handbook on international cooperation in criminal matters against terrorism, developed for trainers in this topic, declares that:Footnote 18
[t]he universal counter-terrorism conventions and protocols do not apply in situations of armed conflict. The International Convention for the Suppression of Terrorist Bombings (1997) and subsequent instruments specify that they are not applicable to acts committed by armed forces during an armed conflict. The branch of international law that is applicable when a situation of armed violence escalates into an armed conflict is that of international humanitarian law, whether the conflict is international or not.
The UNODC relies on the few provisions of cooperation in criminal matters contained in the Geneva instruments only. By contrast, in its handbook on criminal justice responses against terrorism, the UNODC considers that:Footnote 19
[i]t should be understood that the application of international humanitarian law does not in any way prevent or obstruct a criminal justice response to terrorist acts, including the criminalization of incitement, conspiracy and the financing of terrorist acts. It does not prevent offenders from being held accountable by the criminal justice system.
Can then the UN conventions against terrorism, as part of the criminal justice response, be applied to situations of armed conflict? Confusion as to available legal bases is an obstacle to effective cooperation. The predominance of chaos in the system of cooperation in criminal matters benefits actions such as the programme of ‘extraordinary renditions’ of suspects of terrorism, and the subsequent violation of basic fundamental rights.Footnote 20 With the aim of finding a framework that neither leads to the violation of the fundamental rights of terrorist suspects, but nor does it facilitate impunity for the commission of such crimes, I will analyse the regimes that may constitute a legal basis for cooperation in criminal matters against acts of terror committed during armed conflicts, paying particular attention to those committed by foreign terrorist fighters: (i) the rules on criminal responsibility under international humanitarian law (IHL), and (ii) the UN framework of anti-terrorist conventions and UNSC resolutions against foreign terrorist fighters. After analysing the specific content of these different sets of rules, I will conclude that IHL does not necessarily exclude the application of other regimes to acts committed during armed conflict, which can serve as a complementary tool in international efforts for the prevention and suppression of terrorism.Footnote 21
2. Background: UNSC Resolution 2178
The most quoted international instrument against foreign terrorist fighters is UNSC Resolution 2178. In 2014, this resolution provided the first legal definition of the term ‘foreign terrorist fighter’:Footnote 22
Nationals who travel or attempt to travel to a State other than their States of residence or nationality, and other individuals who travel or attempt to travel from their territories to a State other than their States of residence or nationality, for the purpose of the perpetration, planning, or preparation of, or participation in, terrorist acts, or the providing or receiving of terrorist training, including in connection with armed conflicts.
First, there is one important element missing in the definition offered by Resolution 2178: the definition of ‘terrorism’ itself.Footnote 23 The resolution does not give a definition of the crime, nor does it refer to the acts of terror mentioned by UNSC Resolution 1566.Footnote 24 Instead, it leaves the definition of the crime up to each UN member state, an option that has been criticised because the term ‘terrorism’ is commonly used by many states to combat political positions.Footnote 25 Therefore, Resolution 2178 could even be read as an ‘infamous strategy of authoritarian states to have their repression of internal opposition rubber-stamped at the highest level of international law’.Footnote 26
Second, the last sentence of the definition given by the UNSC mentions terrorist acts ‘including in connection with armed conflicts’. These six words have been the target of strong attacks by scholarship because the phrase ‘blurs the lines between terrorism and armed conflicts, not just rhetorically, but by creating legal consequences for “foreign terrorist fighters” who intend to travel abroad’.Footnote 27 For these authors, UNSC Resolution 2178 leads to the erroneous conclusion that every foreign fighter is a terrorist.Footnote 28 The logic of this criticism is undeniable because foreign fighters, as individuals coming from foreign states to participate in an armed conflict, do not necessarily have to participate in terrorist acts but can just conduct themselves according to the rules of IHL.
I also share the conclusion that ‘foreign fighters’ and ‘terrorists’ are not interchangeable terms, and that acts of violence committed by foreign fighters according to the rules of IHL should not be criminalised. However, I also think that we should not read UNSC Resolution 2178 as an instrument written in direct contradiction to the rules of IHL. If we accept the position, which will be defended further in this study, in favour of a parallel application of IHL with other regimes, such as the universal framework against terrorism, we will see that UNSC Resolution 2178 is not necessarily in conflict with IHL.
Apart from this original definition of ‘foreign terrorist fighter’ and its deficiencies regarding the term ‘terrorism’, UNSC Resolution 2178 imposes upon states a wide range of obligations. The existence of effective criminal law measures is among these obligations. Paragraph 6 establishes that all states have the responsibility of ensuring that their criminal legislation is sufficient to properly prosecute and penalise the following conduct: travel or attempting to travel to a state other than a perpetrator's state of residence or nationality for the purpose of terrorism; the wilful provision or collection of funds for terrorist purposes; and the wilful organisation, or other facilitation, of these acts.Footnote 29 In addition, UNSC Resolution 2178, recalling UNSC Resolution 1373, reiterates that:Footnote 30
[Member states shall] afford one another the greatest measure of assistance in connection with criminal investigations or proceedings relating to the financing or support of terrorist acts, including assistance in obtaining evidence in their possession necessary for the proceedings, and underlines the importance of fulfilling this obligation with respect to such investigations or proceedings involving foreign terrorist fighters.
Hence, the use of criminal law measures against terrorism, including the duty to cooperate, is imposed by the UNSC in another example of its role as a ‘universal legislator’.Footnote 31 It is true that these obligations have received many criticisms, mainly because of the impact that ‘pre-emptive criminalisation’ has on the rights of the individual.Footnote 32 However, I will focus only on the impact that UNSC Resolution 2178 has on the link between anti-terrorism criminal law cooperation and IHL.
The wording of UNSC Resolution 2178 repeats that all measures adopted under this instrument must be ‘consistent with international human rights law, international refugee law, and international humanitarian law’.Footnote 33 How can the definition of ‘foreign terrorist fighter’, which includes activities during armed conflict, be consistent with IHL? One could adopt the criticism against UNSC Resolution 2178 and declare the intrinsic inconsistency of criminal measures against foreign terrorist fighters with IHL. By contrast, I consider that the work of the UNSC can be consistent with IHL if the proposition that I will develop during this study is applied.
3. Prohibition and Criminalisation of Acts of Terrorism
3.1. The International Humanitarian Law Framework
IHL does not have the same rationale as other legal branches of international law. This regime is ‘based on the assumption that the use of force is inherent to waging war because the ultimate aim of military operations is to prevail over the enemy's armed forces’.Footnote 34 In fact, Article 43(2) of Additional Protocol I (AP I) expressly recognises the right of combatants to participate directly in hostilities.Footnote 35
However, we should not forget that IHL is also constructed on the basis of core principles that seek to protect the life and properties of civilians, such as the principle of distinction and the prohibition of methods of warfare that can cause superfluous injury or unnecessary suffering.Footnote 36 Therefore, some authors consider that, at first sight, almost every act of terrorism violates these principles, and many others.Footnote 37
Correspondingly, the concept of ‘terror’ is mentioned in several IHL instruments. After the atrocities that took place during the First World War, the Commission on the Responsibility of the Authors of the War and on Enforcement of Penalties presented its 1919 report. The first act that all states had the duty to criminalise was ‘systematic terrorism’.Footnote 38 Similarly, Article 22 of The Hague Rules of Air Warfare establishes that ‘aerial bombardment for the purpose of terrorising the civilian population, of destroying or damaging private property not of a military character, or of injuring non-combatants is prohibited’.Footnote 39
The term ‘terrorism’ appears again in the Geneva instruments after the Second World War. In the context of international armed conflict (IAC), the Fourth Geneva Convention (GC IV) prohibits ‘collective penalties and likewise all measures of intimidation or of terrorism’.Footnote 40 Article 51(2) of AP I also prohibits ‘acts or threats of violence the primary purpose of which is to spread terror among the civilian population’.Footnote 41
In non-international armed conflict (NIAC), Additional Protocol II (AP II) prohibits acts of terrorism against all persons who do not take part or who have ceased to take part in hostilities at any time and in any place whatsoever.Footnote 42 Finally, Article 13(2) of the same instrument establishes that ‘acts or threats of violence the primary purpose of which is to spread terror among the civilian population are prohibited’. Therefore, IHL prohibits acts of terrorism both in IAC and in NIAC.
However, the prohibition of a type of conduct under IHL does not automatically generate individual criminal responsibility. In this sense, Cassese points out that ‘international humanitarian law proscribes terrorism both in international and internal armed conflicts. The question, however, arises of whether, in addition to addressing its prohibition to states, international customary and treaty law also criminalize terrorism in armed conflict’.Footnote 43 This distinction was the basis of many criticisms against the inclusion of the crime of aggression in the Nuremberg Trials, though it was an act that had been prohibited by international law since the Kellogg-Briand Pact of 1928.Footnote 44 Correspondingly, Tomuschat considers that ‘[i]t is one thing to declare war unlawful with regard to inter-state relationships, but a totally different thing to acknowledge it as an offence entailing individual criminal responsibility’.Footnote 45 The establishment of individual criminal responsibility requires overcoming completely different obstacles indeed, as the delay in the ‘activation’ of the crime of aggression in the Rome Statute has proved.Footnote 46
Whereas the activation of the crime of aggression was delayed but successful in the end,Footnote 47 all efforts to include the crime of terrorism in the Rome Statue in the category of war crimes have failed.Footnote 48 Nevertheless, other international instruments give a legal basis for the criminalisation of terrorism during armed conflicts. The Statute of the International Tribunal for Rwanda established its power to prosecute persons who committed or ordered to be committed acts of terrorism, as violations of Common Article 3 to the Geneva Conventions and AP II.Footnote 49 Article 20(f)(iv) of the Draft Code of Crimes against the Peace and Security of Mankind also includes acts of terrorism as war crimes.Footnote 50
The Statute of the International Criminal Tribunal for the Former Yugoslavia (ICTY)Footnote 51 does not include the crime of terrorism specifically. However, this absence has not precluded the tribunal from interpreting that acts of terrorism are included in Article 3 of its Statute as a violation of the laws and uses of war.Footnote 52 This interpretation allowed the tribunal to condemn Stanislav Galić, commander of the Serbian troops during the siege of Sarajevo, for acts of terrorism. The Trial Chamber found that three elements define the crime of terrorism in armed conflicts:Footnote 53
(a) acts of violence directed against the civilian population or individual civilians not taking direct part in hostilities causing death or serious injury to body or health within the civilian population; (b) the offender wilfully made the civilian population or individual civilians not taking direct part in hostilities the object of those acts of violence; (c) the above offence was committed with the primary purpose of spreading terror among the civilian population.
Considering the Geneva instruments and the case law in relation to terrorism and war crimes, Cassese reduces the crime of terrorism in armed conflict to two constitutive elements: ‘the prohibited conduct arguably consists of any violent action or threat of such action against civilians or other persons not taking a direct part in armed hostilities’ (the objective element or actus reus); which is ‘calculated to “spread terror” among the civilian population or other protected persons’ (the subjective element or mens rea).Footnote 54 Following the Galić case, Cassese acknowledges that ‘the purpose of coercing a public (or private) authority to take a certain course of action disappears or, at least, wanes’.Footnote 55
3.2. The UN Conventions Against Terrorism
The failure to define the crime of ‘terrorism’ by the international community is a ‘familiar crux of international law’,Footnote 56 a failure which is the reason why ‘international law concerning terrorism has developed haphazardly and now consists of an unsystematic hodge-podge of treaties concerning specific modes of terrorism’.Footnote 57 These failed efforts survived after the fall of the League of NationsFootnote 58 and persist in the ongoing project for a comprehensive convention against terrorism.Footnote 59
As a result of this failure, most UN conventions do not have a definition of the crime of terrorism. These instruments just contain a list of acts that are typically linked with terrorism and must be criminalised and prosecuted by the state parties, without further reference to any specific intent or motivation. The instruments in relation to civil aviation, from the Tokyo Convention of 1963 to the Beijing Protocol of 2014,Footnote 60 criminalise acts of violence against a person on board an aircraft in flight (and also in airports serving civil aviation); to attempt such acts; or to be an accomplice of a person who performs or attempts to perform such acts; the act of using civil aircraft as a weapon to cause death, injury or damage; the act of using civil aircraft to discharge biological, chemical and nuclear (BCN) weapons or similar substances to cause death, injury or damage, or the act of using such substances to attack civil aircraft; as well as the threat or conspiracy to commit such offences. Similar provisions can be found in the instruments relating to maritime navigation.Footnote 61
In the same line, the Convention for the Suppression of Terrorist BombingsFootnote 62 calls upon states to criminalise the use of explosives and other lethal devices in, into, or against various defined public places with intent to kill or cause serious bodily injury, or with intent to cause extensive destruction of the public place.Footnote 63 The Convention for the Protection of International StaffFootnote 64 also criminalises the intentional murder, kidnapping or other attack upon the person or liberty of an internationally protected person, a violent attack upon the official premises, the private accommodation, or the means of transport of such person; a threat or attempt to commit such an attack; and an act constituting participation as an accomplice.Footnote 65
Only two instruments of the UN convention framework against terrorism include a specific-intent element regarding terrorism. First, the Convention Against the Taking of Hostages provides that an offence is committed by ‘any person who seizes or detains and threatens to kill, to injure, or to continue to detain another person’ (objective element), ‘in order to compel a third party, namely, a State, an international intergovernmental organization, a natural or juridical person, or a group of persons, to do or abstain from doing any act as an explicit or implicit condition for the release of the hostage’ (subjective element).Footnote 66
Second, the Convention for the Suppression of the Financing of Terrorism gives the first full definition of a crime of terrorism when it criminalises the financing of any act ‘intended to cause death or serious bodily injury to a civilian, or to any other person not taking an active part in the hostilities in a situation of armed conflict’ (objective element), ‘when the purpose of such act, by its nature or context, is to intimidate a population, or to compel a government or an international organization to do or to abstain from doing any act’ (subjective element), including the participation and organisation of such financing.Footnote 67
In short, both the Geneva instruments and the UN conventions against terrorism criminalise acts of terror. However, there are some differences between these two systems. The Geneva instruments and their case law define acts of terror according to a wide objective element and a specific subjective element of ‘spreading terror’. Aside from some exceptions, the UN conventions focus simply on the objective element, with a list of acts to be criminalised by the contracting states. In the next two sections I will study how these two definitions can be compatible in order to facilitate the application of the mechanisms of cooperation on criminal matters in the UN conventions against terrorism to situations of armed conflict.
4. International Cooperation Against Terrorism
4.1. General Remarks
According to Wolfrum, the term ‘international cooperation’ describes ‘the voluntary coordinated action of two or more States which takes place under a legal regime and serves a specific objective. To this extent it marks the effort of States to accomplish an objective by joint action, where the activity of a single State cannot achieve the same result’.Footnote 68 Adapting this definition to the object of this study, international cooperation against terrorism may be defined as the voluntary coordinated action of two or more states, which takes place under a legal regime to accomplish the prevention and suppression of terrorism.
Among the different forms of international cooperation, such as diplomatic or military cooperation, this study focuses on cooperation in criminal matters. Bassiouni identifies six modalities within this category: ‘extradition, legal assistance, transfer of criminal proceedings, recognition of foreign penal judgments, transfer of sentenced persons, and freezing and seizing of assets’.Footnote 69 Taking into account the content of the IHL framework and the UN conventions against terrorism, the following sections will focus on the first two modalities: mutual legal assistance and extradition.
On the one hand, mutual legal assistance is defined by Prost as ‘a process by which states seek and provide assistance in gathering evidence for use in criminal cases or in the restraint and confiscation of the proceeds of crime’.Footnote 70 A more exhaustive definition is proposed in the Commentaries on the Additional Protocols: ‘mutual assistance involves the compilation and exchange of information and, in general, any assistance with a view to the tracing, arrest and trial of suspects’.Footnote 71 Cooperation with foreign authorities is particularly important because the authorities of one state cannot, without prior authorisation of the foreign territorial state, conduct any of these activities.Footnote 72 In addition, mechanisms of mutual assistance facilitate the collection of admissible evidence for the purpose of procedures before domestic courts.
On the other hand, extradition designates ‘the official surrender of an alleged offender from justice, regardless of his or her consent, by the authorities of the State of residence to the authorities of another State for the purpose of criminal prosecution or the execution of a sentence’.Footnote 73 Both IHL and the UN conventions include, linked to extradition, articles related to the principle aut dedere aut judicare (the obligation to extradite or prosecute), the modern expression of the Grotian principle known as aut dedere aut punire (the obligation to extradite or punish):Footnote 74
But since for one State to admit within its Territories another foreign Power upon the Score of exacting Punishment is never practised, nor indeed convenient, it seems reasonable that that State where the convicted Offender lives or has taken Shelter, should, upon Application being made to it, either punish the demanded Person according to his Demerits, or else deliver him up to be treated at the Discretion of the injured Party. This is that delivering up so commonly to be met with in History.
Modern terminology replaces ‘punishment’ with ‘prosecution’ as the alternative to extradition in order to reflect the possibility that an alleged offender may be found innocent. In its final report on the topic the International Law Commission (ILC) acknowledged the importance of this principle in the fight against terrorism:Footnote 75
The view that the obligation to extradite or prosecute plays a crucial role in the fight against impunity is widely shared by States; the obligation applies in respect of a wide range of crimes of serious concern to the international community and has been included in all sectoral conventions against international terrorism concluded since 1970.
4.2. The International Humanitarian Law Framework
For IAC, the Geneva Conventions include several provisions for cooperation in criminal matters. Paragraphs 1 and 2 of Article 49 of the First Geneva Convention (GC I) establish that:Footnote 76
1. The High Contracting Parties undertake to enact any legislation necessary to provide effective penal sanctions for persons committing, or ordering to be committed, any of the grave breaches of the present Convention defined in the following Article.
2. Each High Contracting Party shall be under the obligation to search for persons alleged to have committed, or to have ordered to be committed, such grave breaches, and shall bring such persons, regardless of their nationality, before its own courts. It may also, if it prefers, and in accordance with the provisions of its own legislation, hand such persons over for trial to another High Contracting Party concerned, provided such High Contracting Party has made out a prima facie case.
Therefore, this provision asks both for the criminalisation of grave breaches of the Conventions and for the introduction of some sort of aut dedere aut judicare principle, which has also been referred to as primo prosequi, secondo dedere (first to prosecute, second to deliverFootnote 77). Article 88 of AP I also includes the heading ‘Mutual Assistance in Criminal Matters’:
1. The High Contracting Parties shall afford one another the greatest measure of assistance in connexion with criminal proceedings brought in respect of grave breaches of the Conventions or of this Protocol.
2. Subject to the rights and obligations established in the Conventions and in Article 85, paragraph 1, of this Protocol, and when circumstances permit, the High Contracting Parties shall co-operate in the matter of extradition. They shall give due consideration to the request of the State in whose territory the alleged offence has occurred. [emphasis added]
The first paragraph of this article provides no details on the meaning of the obligation to afford ‘the greatest measure of assistance’. The Commentaries on this Protocol suggest that, according to UNGA Resolution 3074, this ‘assistance’ includes, among other activities, ‘compilation and exchange of information, and in general, any assistance with a view to the tracing, arrest and trial of suspects’.Footnote 78 The second paragraph introduces the mechanism of extradition, although it is not entirely clear whether this provision could also serve as a legal basis for extradition in practice between state parties.Footnote 79
In any case, the main question is whether these provisions apply to acts of terrorism committed during an armed conflict, as defined by the Geneva instruments. Each of the articles mentioned above establishes its applicability only to ‘grave breaches’ of the Conventions or the Protocol. The concept of ‘grave breaches’ is defined by Articles 50 of GC I,Footnote 80 51 of GC II,Footnote 81 130 of GC IIIFootnote 82 and 147 of GC IV:Footnote 83
Grave breaches to which the preceding Article relates shall be those involving any of the following acts, if committed against persons or property protected by the Convention: wilful killing, torture or inhuman treatment, including biological experiments, wilfully causing great suffering or serious injury to body or health, and extensive destruction and appropriation of property, not justified by military necessity and carried out unlawfully and wantonly.
Acts of terror are not mentioned specifically in the list of grave offences. Although it is undeniable that acts of terror can include killing or causing serious injury, the specific intent of ‘spreading terror’ required by IHL is still missing. Therefore, a literal interpretationFootnote 84 of the Geneva instruments leads to the inapplicability of IHL provisions relating to cooperation in criminal matters.Footnote 85
Of course, we can ask ourselves whether it would not be better to consider every act of terror within the category of ‘grave breaches’, taking into account just the objective element. In this case it would be possible to apply the IHL regime of cooperation in criminal matters. Although there is no major difference between ‘acts of terror’ and ‘grave breaches’ at first sight, Cassese points out a two-fold difference that justifies our position in favour of the application of the UN conventions against terrorism to scenarios of armed conflict:Footnote 86
First, the extent of the powers of investigation and collection of evidence granted to criminal investigators is different. In the event of those offences being classified as acts of terrorism, those powers are much broader. Secondly, preparatory acts may be criminalized in the case of terrorism, which normally are not, if the actual offence amounts to a war crime.
The legal framework regulating NIAC is much more limited than that for IAC: just Common Article 3 to the Geneva Conventions and their AP II. This framework does not include any provision for cooperation in criminal matters, probably for the following reason: provisions for NIAC regulate purely internal situations, and they do not take into account the presence of international elements (such as foreign fighters), which would make international cooperation necessary in this field.Footnote 87
4.3. The UN Conventions Against Terrorism
Since the Hague Convention, every UN convention for the prevention and suppression of terrorism has included provisions relating to extradition. The Hague Convention introduced the obligation to extradite or prosecute suspects of terrorism, also known as the ‘Hague formula’:Footnote 88
The Contracting State in the territory of which the alleged offender is found shall, if it does not extradite him, be obliged, without exception whatsoever and whether or not the offence was committed in its territory, to submit the case to its competent authorities for the purpose of prosecution. Those authorities shall take their decision in the same manner as in the case of any ordinary offence of a serious nature under the law of that State.
This article has been replicated, in very similar terms, along the entire UN convention framework against terrorism.Footnote 89 Following a literal interpretation of the catalogue of these articles and those included in later conventions, the Secretariat of the ILC concluded that the ‘Hague formula’ imposes an obligation to prosecute ipso facto (by the very fact), with the possible alternative of extradition:Footnote 90
This obligation to prosecute may be said to exist ipso facto in that it arises as soon as the presence of the alleged offender in the territory of the State concerned is ascertained, regardless of any request for extradition. It is only when such a request is made that an alternative course of action becomes available to the State, namely the surrender of the alleged offender to another State for prosecution.
This provision is completed by two more articles. First, Article 8(2) activates the possibility of using the Hague Convention as a legal basis for extradition:
If a Contracting State which makes extradition conditional on the existence of a treaty receives a request for extradition from another Contracting State with which it has no extradition treaty, it may at its option consider this Convention as the legal basis for extradition in respect of the offence.
Therefore, in the absence of a bilateral extradition treaty between the contracting states, any of the UN sectoral conventions against terrorism could be used as a legal basis to extradite those suspected of committing any of the terrorist acts listed in such conventions. Once the legal basis for extradition has been established between both states based on the UN conventions, the exact details of the procedure will follow ‘the procedural provisions and other conditions of the law of the requested State’.Footnote 91
Second, all UN conventions against terrorism include a list of principles of jurisdiction which allow contracting states to establish their jurisdiction for the prosecution, punishment or extradition of those responsible for acts of terror.Footnote 92 While some of these principles are optional (passive nationality and protection), others are mandatory and oblige states to exercise jurisdiction (territoriality and active nationality).Footnote 93 As a result of these principles, contracting states – such as the state of nationality of the suspected terrorist or the state of nationality of the victim – will be able to establish their jurisdiction over such crimes.Footnote 94
Whereas the extradition formula and the principles of jurisdiction have not changed substantially since the first instruments, provisions relating to mutual legal assistance have evolved to confront the mutations of the terrorist threat. In the Hague Convention, Article 10 stated simply the obligation to ‘afford one another the greatest measure of assistance in connection with criminal proceedings’. One year later, the Montreal Convention introduced the obligation to furnish any relevant information when a contracting state has reason to believe that a terrorist act will be committed in another state.Footnote 95 The Convention on the Prevention and Punishment of Crimes against Internationally Protected Persons includes assistance in the collection of evidence, a modality that was not expressly mentioned in earlier instruments.Footnote 96 The Convention against terrorist bombings specifies that mutual assistance is to be provided not only to prosecute terrorist acts, but also in the coordination of criminal and administrative measures to prevent the commission of such offences.Footnote 97 Finally, the Convention for the Suppression of the Financing of Terrorism requires cooperation against the financing of terrorism, including not only from domestic authorities but also financial institutions, and eliminating bank secrecy for this purpose.Footnote 98
To sum up, the IHL instruments relating to cooperation in criminal matters were created for IAC only and, even in this case, these instruments are applicable only in situations of ‘grave breaches’ of IHL, a category that does not specifically include acts of terror. The UN conventions against terrorism have a wider catalogue of instruments of cooperation which are applicable to any act of terror criminalised by such conventions. Taking into account that the IHL system of cooperation in criminal matters does not exist in NIAC and is not applicable to acts of terror as such in IAC, in the following section I will examine how the UN conventions against terrorism can be used to fill the criminal cooperation lacuna in situations of armed conflict.
5. The Interplay between IHL and the UN Conventions Against Terrorism
The provisions of IHL for cooperation in criminal matters do not apply to acts of terror committed during IAC because such acts are not included in the category of ‘serious breaches’ of the Geneva instruments. In the case of crimes committed during NIAC criminal law provisions are non-existent. A literal interpretationFootnote 99 of Article 88(3) of AP I seems to support our claim that other legal regimes for cooperation in criminal matters may be applied in situations of armed conflict:Footnote 100
The law of the High Contracting Party requested shall apply in all cases. The provisions of the preceding paragraphs shall not, however, affect the obligations arising from the provisions of any other treaty of a bilateral or multilateral nature which governs or will govern the whole or part of the subject of mutual assistance in criminal matters.
As some commentators have highlighted, ‘[s]tates remain free to draft such legislation and to conclude such treaties as they wish, within the limits imposed by the obligation to repress by penal measures grave breaches of the Conventions and of the Protocol’.Footnote 101 Although it is not a primary method of interpretation,Footnote 102 the preparatory work also seems to support the conclusion that IHL welcomes the application of other regimes of cooperation in criminal matters: ‘the Conference is not making international penal law but is undertaking to insert in the national penal laws certain acts enumerated as grave breaches of the Convention, which will become crimes when they have been inserted into the national penal laws’.Footnote 103
In the case of terrorism, states wished to develop a framework of universal treaties to combat specific forms of terrorism. This framework could be of great assistance for the prosecution of acts of terror which, as analysed above, are expressly prohibited by IHL. However, there is a tendency to reject this approach. In its handbook for international cooperation against terrorism, the UNODC considers that:Footnote 104
[t]he universal counter-terrorism conventions and protocols do not apply in situations of armed conflict. The International Convention for the Suppression of Terrorist Bombings (1997) and subsequent instruments specify that they are not applicable to acts committed by armed forces during an armed conflict. The branch of international law that is applicable when a situation of armed violence escalates into an armed conflict is that of international humanitarian law, whether the conflict is international or not.
In a very similar way, Pejic argues:Footnote 105
There are several important distinctions between the legal framework governing armed conflict and terrorism, based primarily on the different reality that each seeks to govern. The main divergence is that, in legal terms, armed conflict is a situation in which certain acts of violence are allowed (lawful) and others are prohibited (unlawful), while any act of violence designated as terrorist is always unlawful.
For this reason, this author concludes that ‘with the exception of the few specific acts of terrorism that may take place in armed conflict, it is submitted that the term “act of terrorism” should be reserved for acts of violence committed outside armed conflict’.Footnote 106
In the next pages, I will defend the applicability of several anti-terrorism conventions to acts of terror committed during armed conflict. From my point of view, the existence of legal bases for cooperation in criminal matters is key for the prevention and suppression of terrorism both in times of peace and of armed conflict. As Ferdinandusse points out:Footnote 107
A review of international practice in the investigation and prosecution of core crimes shows that this lack of adequate treaty provisions regarding judicial cooperation has indeed often provided an obstacle in practice, contributing to delays or even failure to prosecute core crimes suspects.
In relation to terrorism, Blakesley and Stigall consider:Footnote 108
the treaties, which comprise the major components of transnational criminal law, therefore, serve to enable much needed international cooperation. If muted, the legal bases for that cooperation are lost and cooperative efforts among states can fail, permitting criminals and terrorists to operate with impunity.
This perspective has been defended by a limited sector of the scholarshipFootnote 109 and by the Court of Justice of the European Union (CJEU). In LTTE Footnote 110 and A and Others Footnote 111 it was asked whether counter-terrorism law could be applicable in times of armed conflict. In both cases the CJEU accepted that counter-terrorism law may apply in conjunction with IHL: ‘The applicability of international humanitarian law to a situation of armed conflict and to acts committed in that context does not imply that legislation on terrorism does not apply to those acts’.Footnote 112 In reaching these conclusions, the CJEU relied on the sources of international law previously mentioned in this study: UNSC Resolution 1373, Article 33 of GC IV, Article 51(2) of AP I, Articles 4(2) and 13(2) of AP II, as well as Article 2(1)(b) of the International Convention for the Suppression of the Financing of Terrorism.Footnote 113
In addition, the Supreme Court of the United Kingdom has supported the application of criminal law paradigms to acts of terror committed during armed conflict. In the case of Mohammed Gul, against the defence argument that qualifying as ‘acts of terrorism’ the acts of non-state groups during NIAC violates the norms of IHL and of the UN conventions against terrorism, the UK Supreme Court stated:Footnote 114
It is true that there are UN Conventions and Council of Europe Conventions concerned with counter-terrorism, which define terrorism as excluding ‘activities of armed forces during an armed conflict’, but there is room for argument as to their precise effect, and, more importantly, it is quite impossible to suggest that there is a plain or consistent approach in UN Conventions on this issue.
The following sections seek to examine how the UN conventions against terrorism can be applied to situations of armed conflict while respecting the norms and principles of IHL. Following the structure and content of the previous sections of this study, I will propose how the material scope of both regimes can be compatible in relation to ‘acts of terror’, and then how can we interpret several UN conventions against terrorism to conclude that their criminal law clauses are applicable to acts of terror committed during armed conflict.
5.1. Acts of Terror in IHL and the UN Conventions
In order to apply the UN conventions to ‘acts of terror’ committed during armed conflicts, it is necessary to have a clear image of what can constitute an ‘act of terror’ in both the UN and the IHL framework.
Starting with the ‘objective element’, we have pointed out that sectoral conventions focus on the criminalisation of specific terrorist acts, which includes acts of violence against civil and maritime transport, internationally protected persons, the taking of hostages and attacks with bombs. The duty to criminalise includes the aiding and abetting of such acts, and also its financing. In the Geneva instruments, the objective element is not limited to specific acts, but includes any violent action or threat of such action against civilians or other persons not taking a direct part in armed hostilities.
Most of the UN conventions against terrorism do not include a specific ‘subjective element’ for the crime of terrorism. The first exception is the Hostages Convention, which includes the specific intent of compelling ‘a third party, namely, a State, an international intergovernmental organization, a natural or juridical person, or a group of persons, to do or to abstain from doing any act as an explicit or implicit condition for the release of the hostage’.Footnote 115 In addition to this element, the Financing of Terrorism Convention includes the specific intent of intimidating a population.Footnote 116 In IHL, taking into account that the very nature of an armed conflict implies the imposition of a form of conduct on an enemy, the intent of ‘compelling’ a state or an international organisation disappears. The only ‘subjective element’ in IHL therefore is the intent to spread terror among the civilian population or other protected persons.
Following the above two elements, I consider that the UN conventions against terrorism are applicable, in the context of armed conflict, to acts of violence committed by non-state groups against civilians or other persons not taking a direct part in armed hostilities (objective element), with the specific intent of spreading terror among the civilian population or other protected persons (subjective element).
5.2. The IHL Exclusion Clauses in the UN Conventions Against Terrorism
We can see that there is an overlap between the field of application of IHL and the UN conventions against terrorism. However, in order to respect the special features of the IHL regime, which permits certain acts of violence considered unlawful under other regimes, it is important to have clear clauses regulating the interplay between IHL and the UN conventions against terrorism. The importance of this task is pointed out by Ferraro in relation to the UN Draft Comprehensive Convention on International Terrorism:Footnote 117
Because of these overlaps and because international conventions addressing terrorism generally apply in situations of armed conflict, it is essential to have in counterterrorism instruments clauses regulating the relationship between IHL and international conventions addressing terrorism. This would be the only way to avoid, as far as possible, the overlaps and contradictions between the two bodies of law. The issue is complex, as exemplified by the discussions surrounding the UN Draft Comprehensive Convention on International Terrorism whose IHL saving clause is one of the main stumbling blocks for completing the drafting process of this instrument. The formulation of such a clause will be critical in order to maintain IHL integrity and rationale, but also to avoid ambiguity and misinterpretation detrimental to IHL. From the ICRC's perspective, any political agreement on the UN Draft Comprehensive Convention on International Terrorism should be translated into a legally correct IHL clause and should not be concluded to the detriment of IHL underlying principles. Such a clause should notably exclude from the scope of the UN Draft Comprehensive Convention on International Terrorism lawful acts of war carried out by parties to armed conflicts.
In the following subsections, I will analyse the exclusion clauses in the UN conventions against terrorism to determine whether and in which situations each of the conventions may be applied to scenarios of armed conflict. I will divide the analysis of the sectoral conventions according to the typology of acts they seek to criminalise as well as the wording of the exclusion clauses: (i) aviation and maritime security, and terrorist bombings; (ii) the taking of hostages; and (iii) the financing of terrorism.
5.2.1. Aviation and Maritime Security
The international conventions on air security of Tokyo (1963),Footnote 118 The Hague (1970)Footnote 119 and Montreal (1971),Footnote 120 as well as the Rome Convention on Maritime Security (1988),Footnote 121 have no exclusion clauses relating to acts of terrorism during armed conflict. The only relevant provision for our purposes establishes that the conventions ‘shall not apply to aircraft used in military, customs or police services’.Footnote 122 This provision has two impacts. First, to apply any of these conventions in times of armed conflict, there must be a civilian target. Second, no attack against a military target in times of NIAC, which can be considered terrorism under certain circumstances in IHL, comes within the field of application of these conventions.
Recent instruments in the field of aviation security – namely, the Beijing Convention (2010)Footnote 123 and the Protocol to the Hague Convention (2010)Footnote 124 – contain an exclusion clause relating to their application to armed conflicts. Article 6(2) of the Beijing Convention establishes that:
[t]he activities of armed forces during an armed conflict, as those terms are understood under international humanitarian law, which are governed by that law are not governed by this Convention, and the activities undertaken by military forces of a State in the exercise of their official duties, inasmuch as they are governed by other rules of international law, are not governed by this Convention.
The International Convention for the Suppression of Terrorist Bombings (Terrorist Bombings Convention) contains, in Article 19(2), the original exclusion clause, which was subsequently transposed into modern maritime and air security conventions. While the Hostages Convention, as we shall see below, makes express references to the Geneva Conventions and their Protocols, the Terrorist Bombings Convention refers generally to IHL, which includes both conventional and customary rules. Leaving aside conventions against the use of certain explosive materials, we already know that attacks against civilian populations are specifically prohibited in the IHL regime, both in IAC and NIAC.
Although the wording is the same as that in the maritime and air security conventions, the logic and consequences of this provision in the Terrorist Bombings Convention are quite different. The maritime and air security conventions include in their field of application only attacks against civilian targets. This means that acts against military forces, both in IAC and NIAC, are completely outside the field of application of these instruments.
The Terrorist Bombings Convention, on the contrary, does not distinguish between attacks against civilian and military targets when requiring state parties to criminalise such acts. Considering that bombs are common weapons in any armed conflict, at first sight it would be impossible to reconcile the IHL regime with the obligation to criminalise such acts. However, a more thoughtful approach to its wording can lead to a different conclusion.
If an explosive device is used against civilians or other internationally protected persons with the intention of spreading terror among the civilian population, such act undoubtedly fulfils the requirements to be considered an ‘act of terror’ under both IHL and the UN conventions. As I mentioned above, IHL does not govern cooperation in criminal matters against acts of terror either in IAC or NIAC because they are not included in the list of ‘serious breaches’ of the Geneva instruments. Under these conditions, therefore, the Terrorist Bombings Convention could serve as a legal basis for cooperation against acts of terrorism involving explosive devices in the context of armed conflict. In the same line, the Beijing Convention and its Protocol can be applied to situations of armed conflict, considering that the target of the terrorist attack is a civilian aircraft.
5.2.2. Hostages
The Hostages Convention establishes that:Footnote 125
[i]n so far as the Geneva Conventions of 1949 for the protection of war victims or the Additional Protocols to those Conventions are applicable to a particular act of hostage-taking, and in so far as States Parties to this Convention are bound under those conventions to prosecute or hand over the hostage-taker, the present Convention shall not apply to an act of hostage-taking committed in the course of armed conflicts as defined in the Geneva Conventions of 1949 and the Protocols thereto, including armed conflicts mentioned in article 1, paragraph 4, of Additional Protocol I of 1977, in which peoples are fighting against colonial domination and alien occupation and against racist regimes in the exercise of their right of self-determination, as enshrined in the Charter of the United Nations and the Declaration on Principles of International Law concerning Friendly Relations and Co-operation among States in accordance with the Charter of the United Nations.
The preparatory worksFootnote 126 for this instrument highlight the legal and political complexities in applying criminal justice measures to situations of armed conflict, especially because of the debate about the legitimacy of national liberation movements.Footnote 127 However, the length of this provision should not lead to confusion. The provision opens a wide range of possibilities to apply the Hostages Convention to acts committed by terrorist groups during armed conflict.
How can we interpret, for the purpose of this study, the wording of Article 12 of the Hostages Convention? First, there are two conditions that must be fulfilled to apply this exclusion clause: (i) the Geneva Conventions or their Protocols are applicable to the specific acts of hostage-taking, and (ii) these instruments bind the state parties involved to prosecute or hand over the hostage-taker. However, as Lambert correctly points out:Footnote 128
The reference to the instruments being ‘applicable’ to the particular act is in fact superfluous since they could hardly require the Parties to extradite or prosecute that offender if they were not ‘applicable’ to that act. Thus, upon closer scrutiny it may be discerned that only one condition must exist in order to make this Convention inapplicable to a particular act of hostage-taking: the Geneva instruments must impose the obligation aut dedere aut judicare with respect to that act.
Therefore, if the Conventions and Protocols are not applicable, states cannot be required to comply with the obligation to extradite or prosecute, at least under the IHL regime. The opposite situation, however, is quite possible: the Geneva instruments would be applicable, but they do not impose an aut dedere aut judicare obligation for the specific act of hostage-taking. We have already pointed out that the IHL regime of cooperation for criminal matters is not applicable in relation to acts of terror as such committed during IAC. In the case of NIAC there is no kind of obligation to extradite or prosecute suspects of acts of terrorism, including hostage-taking. Neither Common Article 3 of the Geneva Conventions nor AP II contain provisions regarding cooperation in criminal matters. Despite the confusing wording, I consider that the ordinary meaningFootnote 129 of Article 12 should lead to the application of the Hostages Convention.
The object and purpose of the treatyFootnote 130 can also support this statement. It seems that the aim of Article 12 is to exclude its applicability to conflicts ‘in which peoples are fighting against colonial domination and alien occupation and against racist regimes in the exercise of their right of self-determination’. Considering that the object and purpose of an individual provision can reflect the general purpose of the treaty,Footnote 131 we could say that one of the purposes of the Hostages Convention is to facilitate criminal cooperation against acts of hostage-taking in armed conflicts while respecting the right of self-determination.
One could argue, however, that Article 13 of the Hostages Convention would exclude its application to internal conflicts: ‘This Convention shall not apply where the offence is committed within a single State, the hostage and the alleged offenders are nationals of that State and the alleged offender is found in the territory of that State’.
Because it is based fundamentally on the principle of territoriality, the exclusion of Article 13 is not difficult to overcome. The Hostages Convention would be applicable, for example, in cases in which the alleged offender is found in a state other than the state in which the criminal act took place or when either the victim or the alleged offender is not a national of the state in which the crimes were committed. In this sense, I believe that the Hostages Convention can be a useful tool against acts of hostage-taking committed by foreign terrorist fighters. Such fighters are, by definition, nationals who travel or attempt to travel to a state other than their state of residence or nationality for the purpose of perpetrating terrorist acts.Footnote 132 In such circumstances, the Hostages Convention opens the possibility of extradition, prosecution and mutual legal assistance.Footnote 133
5.2.3. Terrorist Financing
The Convention for the Suppression of the Financing of Terrorism does not have a specific clause to exclude its application to situations of armed conflict. Hence, following the same line of reasoning as that in the air and maritime security conventions from the 1970s and the 1980s, it should not be difficult to conclude that this convention is applicable to armed conflicts. However, two of its articles impede this intuitive solution.
First, Article 2 establishes the field of application of the offence of providing or collecting funds with the intention that they be used or in the knowledge that they are to be used, in full or in part, to carry out terrorist acts. For the concept of ‘terrorist act’, the second section of Article 2 is divided into two parts:Footnote 134
(a) An act which constitutes an offence within the scope of and as defined in one of the treaties listed in the annex; or
(b) Any other act intended to cause death or serious bodily injury to a civilian, or to any other person not taking an active part in the hostilities in a situation of armed conflict, when the purpose of such act, by its nature or context, is to intimidate a population, or to compel a government or an international organization to do or to abstain from doing any act.
Therefore, the drafters of this clause followed a method similar to the third methodological option for defining terrorism that was proposed by Bassiouni some years prior to the conference: ‘A mixed formula which combines a general (generic) statement and some illustrative applications phrased with specificity of content as to the proscribed conduct’.Footnote 135 It is possible to draw some conclusions from the wording of this provision.
First, the Financing of Terrorism Convention criminalises the financing of any act included in earlier anti-terrorism conventions, from the air and maritime security conventions to the Hostages Convention and the Terrorist Bombings Convention. Whether the financing of one of the listed acts committed during armed conflict comes within the field of application of the Financing of Terrorism Convention will depend on the specific relationship with IHL, examined above, of the applicable instrument.
Second, the financing of any other acts against armed forces in the context of an armed conflict, with the purpose of intimidating a population or compelling a government or an international organisation to do or to abstain from doing any act (dolus specialis), is not included in the field of application of this instrument. This is regardless of whether the means and methods employed can be considered terrorist acts under IHL or regardless of the status of the aggressor. In contrast, Article 2.1(b) clarifies that the financing of any terrorist act against civilians comes within the field of application of this convention, as do attacks against persons not taking an active part in the hostilities in a situation of armed conflict.
The wording of Article 21 of the Financing of Terrorism Convention also affects our research object: ‘Nothing in this Convention shall affect other rights, obligations and responsibilities of States and individuals under international law, in particular the purposes of the Charter of the United Nations, international humanitarian law and other relevant conventions’. For some authors, the effect of this provision is that ‘the conduct, which is considered lawful under IHL, cannot be prohibited under ICSFT [International Convention for the Suppression of Terrorist Financing]’.Footnote 136
Are the acts listed by the Financing of Terrorism Convention considered lawful under IHL? It has already been noted that IHL prohibits acts of terrorism. Considering the fact that certain acts of terror are unlawful (or, at least, not lawful) under IHL, we should accept the application of the Financing of Terrorism Convention to the financing of such acts. For Akande, the purpose of Article 21 is precisely to ‘ensure that the act is nevertheless not prohibited by the Convention where it is consistent with IHL’.Footnote 137 I completely support this statement, and it is the reason why I have used what I consider to be a compatible approach regarding the objective and subjective elements of ‘acts of terror’ in both IHL and the UN conventions. The application of the Financing of Terrorism Convention would not only respect the content of IHL but, in the words of Trapp, ‘it would be its jurisdictional champion – upholding prohibitions under IHL’.Footnote 138
6. Conclusion
The participation of foreign fighters on the side of terrorist groups during armed conflict has raised many questions about the legal basis for the criminal prosecution of acts of terror during such conflicts. In cases regarding the commission of terrorist crimes with transnational elements, such as the foreign nationality of the alleged perpetrator, cooperation with other states in matters such as extradition or mutual legal assistance can be crucial.
When the terrorist attack takes place during an armed conflict, the task of finding legal bases for cooperation becomes particularly complex. Many of the domestic criminal laws of countries involved in armed conflicts rely on international instruments ratified by the state, including the Geneva instruments. However, IHL has a limited set of rules relating to cooperation in criminal matters in scenarios of IAC, which is not applicable to ‘acts of terror’ as such, and there are no rules relating to criminal cooperation in the field of NIAC.
IHL has been seen by many as the only framework applicable to acts committed during armed conflict. In contrast, the position adopted in this article is that IHL does not exclude the simultaneous application of other legal regimes when it does not lead to the criminalisation of acts not prohibited by IHL. Some provisions of the Geneva instruments expressly recognise the applicability of obligations of mutual assistance in criminal matters arising from any other bilateral or multilateral treaty. We should also remember that IHL does not authorise the commission of acts of terrorism; in fact, the opposite is true.
When the UNSC says the ‘preparation of, or participation in, terrorist acts, or the providing or receiving of terrorist training, including in connection with armed conflicts’, the main purpose is to avoid impunity by filling existing gaps in the fight against terrorism with transnational elements, such as in the case of foreign terrorist fighters. In the context of NIAC, it is not inconsistent with IHL to criminalise terrorist acts committed by non-state groups; nor is the use of sectoral conventions to cooperate in the prosecution of those crimes inconsistent. In the context of IAC, this parallel application will be limited by the conditions explained in the sections regarding air security, maritime security, terrorist bombings, the financing of terrorism and hostage-taking.
The UN framework of sectoral conventions against terrorism can compensate for the lack of provisions on cooperation in criminal matters in IHL. Although some of these conventions have clauses that reduce their applicability to armed conflict, those limits are not absolute: most of the air and maritime security conventions can be applied to acts committed by foreign terrorist fighters in situations of armed conflict, as can the Hostages Convention, the Terrorist Bombings Convention and the Financing of Terrorism Convention under the conditions analysed in this article. In addition, all UN conventions may be used, in the absence of an extradition treaty between the contracting states, as a legal basis for the extradition of suspects of terrorism during armed conflicts, an extradition that will then follow the procedural provisions and other conditions of the law of the requested state.
In summary, the simultaneous application of different legal regimes should not be excluded without further reflection. The interaction between IHL and counter-terrorism law proposed by this article explains why several UNSC resolutions have included acts committed during armed conflict as potential terrorist acts. For those states that truly intend to strengthen criminal cooperation against foreign terrorist fighters and against any other act of terrorism committed during an armed conflict, this interpretation also reduces the number of problems associated with the lack of a legal basis for cooperation in criminal matters.
