Terrorist Offences and IHL: The Armed Conflict Exclusion Clause


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| Feb 24, 2022

Armed Conflict Exclusion Clause

In our current article in the International Review of the Red Cross, we discuss the so-called “armed conflict exclusion clause” (also known as an “international humanitarian law (IHL) exclusion clause” or “IHL savings clause”). This clause regulates the relationship between criminal law instruments on terrorism and IHL. While armed conflicts are principally governed by IHL, activities of members of non-state armed groups (NSAGs) and their affiliates may also qualify as terrorist offences.

First, we briefly explain why the concurrent application of IHL and criminal law instruments on terrorism causes friction. Second, we discuss the chief mechanism for dissipating this friction: a clause excluding activities governed by IHL from the scope of criminal law instruments on terrorism. Such armed conflict exclusion clauses exist at the international, regional, and national level. Next, we briefly discuss relevant case law from Canada and Belgium. Based on this case law, we formulate our view on how an exclusion clause can best avoid friction between IHL and criminal law instruments on terrorism.


Criminal law instruments on terrorism and IHL have different rationales. Acts of terrorism are by definition prohibited and criminal. IHL also prohibits certain acts, such as attacking civilians, but at the same time, permits acts that are characteristic to armed conflict, such as attacking military objectives. When States use criminal law instruments on terrorism to punish acts of NSAGs permitted by IHL, they undermine IHL’s dichotomous rationale. Moreover, such a criminalization conflicts with the IHL tenet that parties to an armed conflict have equal rights and obligations. If members of NSAGs are punished for participation in armed conflict regardless of whether they comply with IHL or not, the legal incentive to respect IHL is lost.

In non-international armed conflicts, members of NSAGs do not have a combatant privilege. They can be punished by States for all acts of participation in armed conflict. Nevertheless, at the end of hostilities, States should endeavour to grant the broadest possible amnesty for acts permitted by IHL (see here). This becomes difficult if such acts carry the stigma of terrorism. The terrorism label is a powerful rhetorical tool used by States to condemn and delegitimize their non-State opponents. This precludes the option of negotiation and forestalls the possibility of peace and reconciliation (see notably Saul 2006, 1-22; ICRC 2015, 17-18). Hence, there are sound reasons to exclude activities governed by IHL from the scope of criminal law instruments on terrorism.

International & Regional Level

The “standard” armed conflict exclusion clause first appeared in Article 19(2) of the 1997 Terrorist Bombing Convention. It reads: “The 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.” This clause has now been included in six of the twelve international or “sectoral” anti-terrorism conventions (see here for a list). The clause was controversial from its outset. It remains part of a mix of interrelated issues inhibiting agreement on the Draft Comprehensive Convention on International Terrorism (CCIT).

States currently hold a range of views on armed conflict exclusion clauses. In brief, most Western States (notably including the United States) exclude the military activities of States from the scope of international anti-terrorism conventions. Conversely, a number of predominantly Muslim States oppose the exclusion of “State terrorism” and want to exclude the application of these conventions to wars of national liberation and situations of occupation. Last, a limited number of States favor, or at least favored, an unambiguous extension of the exclusion clause to all activities governed by IHL, including those of NSAGs. However, the latter group of States usually did so only if those activities were “in accordance with” IHL.

The result of the negotiations in 1997 was an ambiguous clause. According to some, the notion of “armed forces” extends to NSAGs. According to others—and this seems to have become the prevailing view during the negotiations for a CCIT—it refers only to the activities of State armed forces.

Quite clearly, the wording of the standard exclusion clause is not, or at least is no longer, accepted across regions. This explains why the clause has been copied into regional legal instruments only in Europe (see Article 26(5) of the 2005 Council of Europe Convention on the Prevention of Terrorism; Recital 37 of the 2017 EU Directive on the combating of terrorism).

National Level

Switzerland, the United States, and Ireland have “offence-specific clauses.” These clauses follow the wording of the specific sectoral convention or regional criminal law instrument on terrorism that they implement and attach to the corresponding domestic terrorist offence.

The Swiss Criminal Code provides that there is no offence of terrorist financing “if the financing is intended to support acts that do not violate the rules of international law on the conduct of armed conflicts,” reflecting Article 2(1)(b) of the 1999 Terrorist Financing Convention. The United States attaches the standard exclusion clause to the offence of acts of nuclear terrorism and that of terrorist bombings. The offence of terrorist financing implements the clause of the 1999 Convention. As noted by the United Kingdom Supreme Court, the position of the United States on the exclusion clause is “ambivalent,” as some of its provisions on terrorism are ”widely drawn without the exclusion” (R v Gul 2013, para. 51). Ireland attaches the standard exclusion clause to the criminal law provision on terrorist offences and the offence of terrorist bombing, while the offence of hostage taking and financing of terrorism include the exclusion clauses contained in the 1979 Hostages Convention and 1999 Financing Convention, respectively.

South Africa, Canada, New Zealand and Belgium have what we call “general clauses.” These clauses apply to terrorist offences in that State’s criminal legislation in general and extend to group offences like participation in the activities of a terrorist group.

The South African clause excludes acts in accordance with IHL only for wars of national liberation (see Section 1(4) of the 2005 Protection of Constitutional Democracy Act). The Canadian Criminal Code’s definition of “terrorist activity” provides that it “does not include an act or omission that is committed during an armed conflict and that, at the time and in the place of its commission, is in accordance with customary international law or conventional international law applicable to the conflict.” In New Zealand, the Terrorism Suppression Act of 2002 general definition of a “terrorist act” contains a similar exclusion. Article 141bis of the Belgian Criminal Code excludes the activities of armed forces governed by IHL completely from the application of the Code’s entire chapter on terrorist offences.

Although it applies only to the activities of “armed forces,” the Belgian clause is the broadest: it is general (not offence-specific); it covers all acts governed by IHL (not just acts in accordance with IHL); and it covers all situations of armed conflict (notably, it is not limited to wars of national liberation). The Canadian and New Zealand clauses are not limited to the activities of armed forces, but only cover acts in accordance with IHL.

Case Law

Beyond statutory provisions, case law has developed doctrine concerning armed conflict exclusions from criminal law. In Canada, the most relevant case is R v Khawaja. Khawaja is a Canadian citizen who from 2002 to 2004 was part of the “Kyam group,” a small jihadist group operating from the United Kingdom. In Canada, Khawaja created a device to remotely detonate explosives. He also travelled to Pakistan to train for armed combat in Afghanistan, but never participated in hostilities.

In 2005, Khawaja was charged with a range of terrorist offences under the Canadian Criminal Code. Khawaja argued that he only wanted to participate in the armed conflict in Afghanistan and that due to the exclusion clause, his acts fell outside the definition of terrorist activity. The courts disagreed. There was no evidence that Khawaja or the insurgents in Afghanistan acted in accordance with IHL (quite the contrary) and Khawaja’s activities did not solely relate to the armed conflict in Afghanistan (see respectively Ontario Superior Court of Justice (paras 125-132), Court of Appeal for Ontario (paras 152-169) and Supreme Court of Canada (paras 95-103)).

In Belgium, courts did not apply the exclusion clause for many years. This changed with a case concerning the Kurdistan Workers Party (PKK). Belgium prosecuted 40 individuals for participation in the activities of a terrorist group, among others. Prosecutors alleged that from 2004 to 2014 the accused had organized events in Belgium to finance the PKK. The defendants argued that their activities related to the armed conflict between Turkey and the PKK (see, e.g., here), such that they could not be convicted for terrorist offences. The courts agreed.

The Court of Appeal of Brussels (2019) held that the definition of a terrorist group in the Belgian Criminal Code requires that the group operates to commit physical terrorist acts. While the PKK had committed such acts, these acts were all committed within the geographical scope of the conflict with Turkey and had a nexus to that conflict. Hence, the acts fell under the exclusion clause. By consequence, the PKK was not a terrorist group in the sense of the Belgian Criminal Code, and mere participation in its activities was not a terrorist offence. The case was dismissed (on the Belgian case law, see this blog post).

Scope of the Exclusion Clause

It is important to stress that IHL does not prohibit States from prosecuting activities committed by NSAGs, whether as terrorist or common criminal law offences. It seems that, at least as a matter of international law, neither does any exclusion clause. However, once States implement an exclusion clause into their domestic legislation, the clause regulates the relationship between the State’s domestic criminal law provisions on terrorism and IHL in a compulsory way. The clause limits the extent to which activities committed in relation to armed conflicts can constitute terrorist offences. It does not affect the possible qualification of these activities as international crimes or common criminal law offences under domestic law.

Given the friction between IHL and criminal law instruments on terrorism, we argue that any such instrument (international, regional, as well as national) should contain an exclusion clause providing that the relevant instrument does not apply to activities governed by IHL. If the activities are permitted by IHL, they should not be prosecuted as terrorist activities. If the main (direct) offences benefit from the application of the exclusion clause, ancillary (indirect) offences should as well (cp. Coco 2013, 435; Penny 2009, 426; Trapp 2012).

However, the protection of the exclusion clause stops where a group commits or intends to commit violence “outside the context of armed conflict,” be it in a geographical sense (in which case the assessment depends on one’s approach to the geographical scope of application of IHL), or because the acts do not have a nexus to the armed conflict, or both. Hence, a NSAG like Islamic State that is a party to an armed conflict is also a terrorist group and has a “dual nature” (cp. Cuyckens & Paulussen 2019, 562). In our opinion, this is the case for the group “as such” or ”as a whole,” unless the group committing terrorist acts outside the context of armed conflict can be separated from the group only operating within that context.

Also, for groups with a dual nature, activities governed by IHL should not be assessed under criminal law instruments on terrorism, above all to prevent acts permitted by IHL from being prosecuted as terrorism. Acts prohibited by IHL should be prosecuted as war crimes rather than as terrorist offences. Activities not governed by IHL can constitute terrorist offences.

Notably, the financing of and recruitment of members for dual nature groups are (indirect) terrorist offences. There can only be an exception if the activities are exclusively connected to activities governed by IHL. If they are, and if such activities are permitted under IHL, those who contribute should not be prosecuted for terrorist offences. If they contribute to acts prohibited by IHL, these persons can be prosecuted for war crimes (see the flowchart below).

This approach preserves the integrity of IHL by ensuring that the activities of NSAGs permitted by IHL are excluded from prosecution as terrorist offences, while violations of IHL are prosecuted and punished for what they are: war crimes.


Thomas Van Poecke is a PhD Fellow at the Research Foundation – Flanders, affiliated to the Institute for International Law and Leuven Centre for Global Governance Studies, KU Leuven.

Frank Verbruggen is a Professor of European and International Criminal Law at the Institute of Criminal Law and Leuven Centre for Global Governance Studies, KU Leuven.

Ward Yperman is a PhD Researcher and Teaching Assistant at the Institute of Criminal Law, KU Leuven.