The Overlap Between IHL and International Counterterrorism Law

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In the past few decades, there has been a rise in the threats that states face from non-state armed groups and individuals which use terrorism as a method of combat. As a response, states, in cooperation with international organizations, have developed vigorous counterterrorist tools in the form of international conventions and the incorporation of counterterrorism law in domestic criminal law. The resulting law on counterterrorism– collectively formed by twelve international legal instruments – often collides with the human-centric purpose and the objective of IHL by skewing security towards the state instead of the individual.1“From Conflict to Complementarity: Reconciling International Counterterrorism Law and International Humanitarian Law.” International Review of the Red Cross, 1 Feb. 2022, The question of which regime applies and when is also a controversial topic. For instance, several African, Middle Eastern, and Asian states have carried out counterterrorism operations in situations of armed conflict.2“International Humanitarian Law and the Challenges of Contemporary Armed Conflict.” International Committee of the Red Cross, 16 June 2020, pp. 57–61., The concern for IHL in this scenario stems from the different protections and obligations for states under CTL by designating non-state armed groups as terrorists in situations which are otherwise classified as armed conflicts under IHL. This article aims to examine the interaction that exists, or the lack of it, between CTL and IHL. It seeks to recognize the need to create harmony between CTL and IHL in order to avoid fragmentation in international law which occurs when there are too many regimes regulating the same conduct. 

Armed Conflict or Terrorism?

International counterterrorism law has been framed within twelve international legal instruments, the first of which dates back to 1963, each of which seek to prevent terrorist incidents from taking place.3 “United Nations, UN Treaties.” United Nations, A discussion on the contention between IHL and CTL requires an understanding of where the two apply i.e. armed conflicts and acts of terrorism. In essence, terrorism and armed conflict are not mutually exclusive. Acts of terrorism may take place in situations of armed conflicts.4Poecke, Thomas Van, et al. “Terrorist Offences and IHL: The Armed Conflict Exclusion Clause.” Lieber Institute West Point, 25 Feb. 2022, The most basic divergence between the two is that in an armed conflict, a number of given acts of violence are categorically permissible (for instance proportionate attacks against military objectives) while others are delineated as impermissible (such as targeting civilians).5 “IHL Challenges Report .” International Committee of the Red Cross, 2011, Whereas, any and every act that is classified as a terrorist act is always impermissible and unlawful under the framework of the CTL regime.6Ibid.

In an armed conflict, the objective of parties is to triumph over their opponent’s forces, for the purpose of which acts of violence towards the enemy’s personnel or objects, which are aimed towards gaining military advantage, are permissible under IHL.7“The Applicability of IHL to Terrorism and Counterterrorism.” International Committee of the Red Cross, 30 Nov. 2020, The permissibility of such acts of violence remains independent of whether the party carrying out the acts is a state actor or a non-state one.8Ibid.

With regard to terrorism, unfortunately, international law provides no definition of the term due to different political and ideological interpretations.9“The Practical Guide to Humanitarian Law.” Doctors Without Borders | The Practical Guide to Humanitarian Law, Article 2 (1)(b) of the 1999 Convention for the Suppression of Financing Terrorism defines it as ‘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, when the purpose of such an act, by its nature or context, is to intimidate a population or to compel a government or an international organization to do or abstain from doing any act’.10“International Convention for the Suppression of the Financing of Terrorism, Adopted by the General Assembly of the United Nations on 9 December 1999.” UN Treaty Collection, The UN Resolution 1566, 2004 defines criminal acts, which are carried out against civilians, with an intention to cause physical harm; or the taking of hostages, with the specific purpose of provoking terror among the people and to compel an authority into doing or abstaining from an act.11“Security Council Resolution 1566 (2004) on Threats to International Peace and Security Caused by Terrorist Acts – United Nations and the Rule of Law.” United Nations, Such acts have been repeatedly forbidden under IHL which classifies them as completely illegal on the basis of such acts being indiscriminate, targeting protected persons, including civilians; and the taking of hostages.12“Article 48.” Treaties, States Parties, and Commentaries – Additional Protocol (I) to the Geneva Conventions, 1977 – 48 – Basic Rule,“Article 3.” Treaties, States Parties, and Commentaries – Geneva Convention (III) on Prisoners of War, 1949 – 3 – Conflicts Not of an International Character, “Fundamental Principles of IHL.” Fundamental Principles of IHL | How Does Law Protect in War? – Online Casebook,

The Friction between IHL and Counterterrorism

Fundamentally, some of the friction between IHL and CTL stems from the fact that most of the acts which have been listed down under CTL have already been addressed by IHL. Article 33 of the Fourth Geneva Convention and Article 4 (2)(d) of Additional Protocol II categorically prohibit acts of terrorism.15“Article 33.” Treaties, States Parties, and Commentaries – Geneva Convention (IV) on Civilians, 1949 – 33 – Individual Responsibility, Collective Penalties, Pillage, Reprisals,“Article 4 (2)(d)” Treaties, States Parties, and Commentaries – Additional Protocol (II) to the Geneva Conventions, 1977 – 4 – Fundamental Guarantees, Article 51 (2) of Additional Protocol I and Article 13 of AP II again prohibit any acts of terrorism i.e. acts of violence which have ‘the primary purpose of spreading terror among civilians’ are expressly forbidden in the conduct of hostilities.17“Article 51 (2).” Treaties, States Parties, and Commentaries – Additional Protocol (I) to the Geneva Conventions, 1977 – 51 – Protection of the Civilian Population,“Article 13.” Treaties, States Parties, and Commentaries – Additional Protocol (II) to the Geneva Conventions, 1977 – 13 – Protection of the Civilian Population, Furthering the argument is the prohibition of indiscriminate and disproportionate attacks under IHL and the prohibition from attacking targets other than military ones i.e. civilians or civilian object.19“Fundamental Principles of IHL.” Fundamental Principles of IHL | How Does Law Protect in War? – Online Casebook, The pursuit of these principles would automatically mitigate the threat of terrorism. 

In addition to the resistance shown by states to the application of IHL to their CT measures, there are some inherent clashes that CTL faces with IHL. Despite its purpose of counterterrorism, efforts have been made under CTL which restrain and monitor every activity of organizations that, directly or indirectly, provide sponsorship or support to NSAGs that have been designated as ‘terrorists’ by State.20“International Convention for the Suppression of the Financing of Terrorism, Adopted by the General Assembly of the United Nations on 9 December 1999.” UN Treaty Collection, In this regard, the 1999 Convention on Terror Financing imposes many restraints on financing of groups listed as ‘terrorist’. This may prevent humanitarian organizations such as the ICRC from performing their operations properly by denying humanitarian aid to those who require it as it may be perceived as terrorist financing.21“Principles under Pressure: The Impact of Counterterrorism Measures and Preventing/Countering Violent Extremism on Principled Humanitarian Action.” Norwegian Refugee Council, 2018, Restrictions on the sponsorship of NSAGs designated as ‘terrorists’ under CTL goes to the extent of agreements between donors and humanitarian organizations as a result of which no room is left of impartial humanitarian action.22Ibid. Article 1(d) of UNSC Resolution 1373 of 2001 for instance, states that prohibitions are to be imposed on nationals by their respective states “from making any funds, financial assets or economic resources or financial or other related services available, directly or indirectly, for the benefit of persons who commit or attempt to commit or facilitate or participate in the commission of terrorist acts, of entities owned or controlled, directly or indirectly …”.23“Article 1.” Resolution 1373 (2001). The ambiguity over the terms ‘support’ and ‘other related services’ has led to every State using its interpretation and in practice often result in the hampering of the provision of medical aid, first aid training, and facilitation of family visits and other human rights and humanitarian action.24“IHL Challenges Report .” International Committee of the Red Cross, 2011,

Dissipating the Friction between IHL and CTL

The adoption of UNSC Resolution 1373 in the aftermath of the 9/11 attacks on the United States led to a creation of a transnational counterterrorism law that obliged states to criminalise acts of terrorism and its financing.25Poecke, Thomas Van, et al. “Terrorist Offences and IHL: The Armed Conflict Exclusion Clause.” Lieber Institute West Point, 25 Feb. 2022, The UNSC requires States to stop supporting and financing terrorism, without providing a working definition of what acts constitute as terrorism – leaving it up to States to define it for themselves.26“Chapter VII: Action with Respect to Threats to the Peace, Breaches of the Peace, and Acts of Aggression (Articles 39-51).” United Nations, The UNSC Resolution further conflates this regime with IHL by subsuming situations of armed conflict under acts of terrorism and by remaining silent on providing an explicit exclusion clause for IHL.27“Chapter VII: Action with Respect to Threats to the Peace, Breaches of the Peace, and Acts of Aggression (Articles 39-51).” United Nations,

However, in the conflict between IHL and CTL, the standard ‘exclusion clause’, provides a ray of hope in harmonizing the two legal systems. Included in six of the international terrorist conventions, it has become the most cited clause on armed conflict exclusion, since 1997 when it was first included in the Convention on Terrorist Bombings under Article 19 (2) which states that ‘the activities of armed forces during an armed conflict, as those terms are understood under the IHL, which are governed by that law, are not governed by this Convention’.28“International Convention for the Suppression of Terrorist Bombings, Adopted by the General Assembly of the United Nations on 15 December 1997.” UN Treaty Collection,, Thomas Van, et al. “Terrorist Offences and IHL: The Armed Conflict Exclusion Clause.” Lieber Institute West Point, 25 Feb. 2022, Despite the disagreements and controversies surrounding the clause over its applicability over State military activities, the exclusion clause acts as a prototype of a bridge between IHL and CTL. 

In 2019, two major revolutionary efforts were made by the UN to harmonize CTL with IHL with the adoption of UNSC Resolutions 2462 and 2482, which have made a far more explicit effort for the compliance of counterterrorism measures with IHL and thereby secure impartial humanitarian action.30Weizmann, Nathalie. “Respecting International Humanitarian Law and Safeguarding Humanitarian Action in Counterterrorism Measures: United Nations Security Council Resolutions 2462 and 2482 Point the Way.” International Review of the Red Cross, 1 Feb. 2022, Paragraph 5 of Resolution 2462 requires States to criminalize terror financing while remaining consistent with the obligations of IHL.31“Resolution 2462, Adopted by the Security Council at its 8496th Meeting on March 28, 2019”. United Nations.”, URL: Article 6 of the same resolution requires member states to ascertain that all counterterrorism measures taken, inclusive of terror financing, comply with IHL, IHRL and international refugee law.32Ibid. Resolution 2482 attempts at harmonizing IHL and CTL under Paragraph 16 which, in a similar manner to the obligations of Resolution 2462, insists that all the counterterrorist measures of States should remain within the limits of their obligations under humanitarian law.33“Resolution 2482 (2019) Adopted by the Security Council at its 8582nd meeting, on 19 July 2019.”, URL: Both these resolutions are understood to play a huge part in evolving the international counterterrorism regime into one that acknowledges IHL in its practice.

Despite the grand purpose of uniting CTL and IHL behind Resolutions 2382 and 2462, the contention between the interpretations of the two continues. The preamble of both the resolutions includes statements under which compliance with IHL is ensured, yet references to IHL in the subsequent paragraphs are frequently missing.34“UNSC Resolution 2482.” United Nations,“UNSC Resolution 2462.” ODS, Similarly, the exclusion clause has become more a cause for contention than resolution. Stated under Article 19(2) of the 1997 Terrorist Bombings 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, and the activities undertaken by the 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”.36“International Convention on the Suppression on Terrorist Bombings, New York, 15 December, 1997.” United Nations, United Nations Treaties, The two-pronged clause – the first prong which deals with armed forces in an armed conflict, and the second prong which refers to law enforcement and peacekeeping operations carried out by the State – is particularly contentious with regard to its latter half. Most Western states, predominantly the USA, want to exclude the activity of their military forces from the bounds of the Convention. In contrast, most Muslim States and regional organizations, namely the African Union, Organization of the Islamic Conference, and the other Arab region conventions,  find the immunity of state militaries stated under the clause as problematic in cases of State terrorism.37Poecke, Thomas Van. “Terrorist Offences and International Humanitarian Law: The Armed Conflict Exclusion Clause.” International Review of the Red Cross, 1 Feb. 2022, Yet, simultaneously, most Muslim states, most vocally Pakistan and the Syrian Arab Republic, reject the exclusion of state terrorism from the interpretation of the clause and instead want to exclude the application of counterterrorism conventions from wars of national liberation and instances of foreign occupation.38Ibid.

This unearths the age-old problem of ‘one man’s freedom fighter is another man’s terrorist’. Terrorism in itself is merely a tactic, often comparable to war. Although unlike war, the key characteristics of terrorism are its indirect approach and its attacks on non-combatants through which terrorists seek to send a message to the public and instill fear.39Finlay, Christopher J. Terrorism and the Right to Resist: A Theory of Just Revolutionary War. Cambridge University Press, 2015.40Goodin, Robert E. What’s Wrong with Terrorism? Polity, 2007 In a similar streak, the employance of violence in war is for communicative purposes too.41Nathanson, Stephen. Terrorism and the Ethics of War. Cambridge University Press, 2010 Despite the similarities in characteristics of war and terrorism, the issue at hand is not to equate the two but to bring out the legislations governing the two on the same ground. The law on counterterrorism, with reference to the conventions on the theft of nuclear material or the convention on the marking of plastic explosives, addresses issues upon which IHL has not elaborated.42Saul, Ben. “Order from Chaos: The Optimal Relationship between International Counter-Terrorism Law and International Humanitarian Law.” OHCHR, Additionally, CTL can also be thought of as more rapid and swift in its punishment through ‘listing’ as compared to the drawn-out trials for war crimes in international criminal tribunals.43Ibid. Yet what needs to be emphasized is that it is precisely due to the overly-cautious methodology of IHL through which impartiality is guaranteed for all the parties in an armed conflict and ensures that State actors too are not immune from excessiveness in their actions against NSAGs or designated ‘terrorists’. Further, IHL respects the rights of the State to prosecute an individual or an organization under its domestic criminal legislation as terrorism.

The 2012 R v Khawaja case against Mohammad Momin Khawaja, a Canadian citizen, who was part of the British jehadist group, Kyam, employed the exclusion clause as per the Canadian interpretation. Khawaja had created a device which could remotely operate explosives and he also went for training exercises for the conflict in Afghanistan to Pakistan, although never participated in direct hostilities. Upon being charged with terrorism in 2005, he argued that since his activities were part of the armed conflict in Afghanistan, the exclusion clause should be applied. However, investigation revealed that Khawaja’s activities were not within the scope of that armed conflict; thereby, he was convicted under the law applicable to counter-terrorism.44R. v. Khawaja, 2012 SCC 69, [2012] 3 S.C.R. 55545Verbruggen, Frank, and Ward Yperman. “Terrorist Offences and IHL: The Armed Conflict Exclusion Clause.” Lieber Institute West Point, 25 Feb. 2022, The successful application of the exclusion clause in R v Khawaja case shows a ray of hope for how CTL and IHL can be co-applied.


The laws of armed conflict and the counterterrorism regimes collide with each other primarily over the varying duties they require in the same situation i.e. they are often applied in the same situation but differ in the obligations they impose. The UN Resolutions 2462 and 2482 along with the exclusion clause provide a middle ground by trying to link the two sets of legal regimes. However, the interpretation and application of these, as well, namely, the exclusion clause remains a contested subject. States hold a myriad of views of its applicability. It must be understood; however, that IHL in no way prevents the prosecution of unlawful offenses under counterterrorism or criminal law; however, as soon as a State implements the exclusion clause in its domestic law, it is obligated to factor in the provisions of IHL. The protections of the exclusion clause are limited to only those acts of violence which are committed within the context of an armed conflict, something which has become tricky to determine due to the urbanization and globalization of conflict.46Poecke, Thomas Van, et al. “Terrorist Offences and IHL: The Armed Conflict Exclusion Clause.” Lieber Institute West Point, 25 Feb. 2022,, Hamish. “R. v. Khawaja: At the Limits of Fundamental Justice.” York University, The Supreme Court Law Review – Osgoode School of Law, 2013,

The duality of NSAGs, such as the Islamic State, has cast doubt as to whether to assess their activities under CTL or IHL due to their participation in an armed conflict as a designated terrorist group. In such scenarios, the context in which the activities are being carried out i.e. situation of armed conflict or not should be factored in. Where there is an armed conflict and IHL violations occur, including terrorism, then those actions should be prosecuted as war crimes rather than under the auspices of CTL.48Ibid 46.

The fact remains that despite the overlap that exists between IHL and CTL, the utility for CTL is required in areas where hostilities have not reached a point of intensity and therefore are not characterized as an armed conflict.49“Non-International Armed Conflict.” Non-International Armed Conflict | How Does Law Protect in War? – Online Casebook, However, it can be argued that the intensity of the civilian suffering caused by an isolated terrorist attack is enough to categorize an act of violence as the commencement of an armed conflict and hence obligating the application of IHL. Thus, it can be deduced that due to the very complicated nature of acts of terrorism and instances of armed conflict and the interrelationship between the two, CTL and IHL are bound to collide and overlap with each other. In this regard, to date, the best solution has been provided by UNSC Resolutions 2462 and 2482 which provide a horizon on which CTL and IHL can function together.


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Tajwer Shamsi
Tajwer Shamsi is currently completing her Masters in Security and Strategic Studies. She holds an undergraduate degree in International Relations. Her areas of interest include Nationalism and Ethnic Studies, International Law, Geopolitics, and Security Studies. She is available at [email protected]