With an ever-increasing number of non-State armed groups and a growing tendency for non-international armed conflicts (NIAC) to be fought by coalitions, it is crucial that our interpretation of international humanitarian law (IHL) continues to reflect realities on the ground. In this post, ICRC legal advisors Jelena Nikolic, Thomas de Saint Maurice, and Tristan Ferraro suggest that in situations where there is evidence that non-State armed groups (NSAGs) have objectively and effectively adopted a collective approach to fighting against a common enemy, the intensity criterion required by IHL for determining the existence of a NIAC should be assessed on the basis of the aggregation of the military actions carried out between all the NSAGs fighting together and their common enemy, rather than requiring that each bilateral relationship of violence meets the criterion on its own.


According to research by Small Arms Survey, there were 236 separate armed groups registered in just one city – Misrata, Libya – in October 2011. Across the Sahel, various armed groups operate with different structures and motives, some of which are functioning under umbrella organizations such as the JNIM.[1] In Syria, the armed conflict has sparked the creation of a wide array of armed groups since 2012.[2]

Libya, the Sahel and Syria are just a few exemplary contexts where the number of armed groups involved in the violence has skyrocketed. Among the patterns of evolution of warfare[3], one is certainly the multiplication of actors participating in the violence.[4] An important number of non-international armed conflicts (NIACs) today involve two or more parties fighting on the same side against a common enemy or common enemies. There is a growing tendency for NIACs to be fought in coalitions, with a number of States or armed groups joining forces and State militaries partnering with armed groups.[5]

These complex situations pose obvious challenges to determining the legal framework applicable when violence erupts, as it is often difficult to have a comprehensive understanding of the structure and organization levels of various actors, their involvement in the armed confrontation, or the relationships between them. This also makes it difficult to identify the groups that could be considered as parties to armed conflicts under international humanitarian law (IHL), as well as the role of each actor in the violence.

In some situations, the activities of distinct armed groups might not reach a sufficient level of intensity to reach the threshold of a NIAC when looked at separately and individually. However, the circumstances prevailing in some contexts may require to slightly zoom out as the military actions of these groups often appear to be closely connected with the operations undertaken by other belligerents, which may justify an analysis taking into account the collective dimension of the fighting.

When does international humanitarian law apply?

International humanitarian law does not apply to ‘internal disturbances and tensions, such as riots, isolated and sporadic acts of violence and other acts of a similar nature’.[6] This is because IHL has been tailored for exceptional situations of organized armed violence, in which regular, classic means and methods aimed at restoring law and order are not adequate to respond to the threat emanating from organized armed groups. On the other hand, in situations that do not meet the threshold of an armed conflict, law enforcement measures regulated by human rights law are sufficient to contain the violence.

With this in mind, to classify a situation of violence as a NIAC, two criteria are required under IHL: confrontations must take place between at least two organized parties, and the violence must have reached a certain level of intensity.[7]

Clearly, IHL should not apply if the actors involved do not possess a minimal level of organization, generally manifested by a certain command structure. IHL requires that the parties to armed conflicts have the capacity to conduct military operations and to apply IHL rules.

In practice, it is not always easy nor straightforward to determine if an armed group is sufficiently organized for the purposes of IHL application. This determination may be more difficult when a myriad of non-State armed groups are operating in a context. This was for example demonstrated by the escalation of protests in Syria in 2011, gradually leading to hostilities between the government forces and different armed opposition groups operating in the country, estimated to be in the hundreds, which quickly affected many areas in the country, with significant consequences on the local population.[8] In such situations where numerous armed actors are involved in hostilities, the first step is thus to identify those who meet the organization criterion[9] as IHL cannot apply to actors involved in the violence who do not satisfy the organization criterion.

On the other hand, when armed groups satisfying the organization criterion coalesce and conduct coordinated military operations against the same adversary(ies), at what point would it be operationally and legally sound to consider a NIAC has started and IHL has become the applicable legal framework? Should the IHL criteria of intensity be applied individually to each and every bilateral belligerent relationship potentially leading to a situation in which only some organized armed groups fighting alongside may be considered as parties to the NIAC while others would not and could only be dealt with under the law enforcement paradigm/human rights law? Would it make more sense to assess the criterion of intensity taking into account the collective nature of the fighting instead?

Usually, the level of intensity is assessed for each bilateral situation of violence on its own, meaning that armed confrontations between an organized armed actor and its adversary would need to satisfy the criterion of intensity, regardless and separately from the actions of other organized armed actors that might be fighting the same adversary. However, the strict application of this ‘fragmented approach’ may lead to a legal and operational loophole in situations where there is a clear coordination between organized armed actors which would put the reality on the ground and the legal analysis at odds. Indeed, it risks denying the existence of military operations undertaken collectively and thus leading to a conclusion that for some of the armed groups in the coalition IHL is applicable, while for others it is not.

Aggregating the intensity?

In some contexts, such as in Syria, Libya, or the Sahel, several armed groups, often locally formed but distinct entities sharing a similar military goal, joined forces in fighting against a common enemy, often the State.

Considering the complexity of these situations, the number of actors involved, as well as the certain level of common purpose and coordination between the actors, it might be both practically impossible and legally illogical to look at bilateral confrontations and disentangle the level of violence by each of the armed groups involved. In such situations of emerging violence wherein it needs to be assessed if the threshold of a NIAC has been reached, it might therefore be more legally sound to consider aggregating the intensity of identified organized NSAGs for the classification purposes.

This is what the ICRC has submitted in its 2019 report recently published on International humanitarian law and the challenges of contemporary armed conflicts: ‘[w]hen several organized armed groups display a form of coordination and cooperation, it might be more realistic to examine the intensity criterion collectively by considering the sum of the military actions carried out by all of them fighting together.’[10]

Under what conditions could we use such an approach to classify new NIACs? As mentioned above, a first condition will be that the armed groups operating together are all organized for IHL purposes. We submit that another necessary condition would be that these groups are essentially operating in some sort of a coalition, objectively and effectively demonstrating a collective approach of the fighting.

In some situations, coalitions might be open and public, while in others the coordination between the parties might be much more covert or implicit (e.g. simultaneous or coordinated attacks against the same enemy in different parts of the country, conducting military operations based on the intelligence collected by another armed actor and similar).

The criteria to assess whether there is a sufficient level of coordination in a coalition are not set in law, but are instead based on factual considerations and should be assessed on a case by case basis. Several elements could be considered to assess the existence of a ‘coalition’, such as: establishment of centralized joint command, allocation of areas of responsibilities, sharing of operational tasks (detention, procurement, equipment, transport of troops and other logistics), declarations / agreements describing the tasks assigned to coalition members, existence of common Standard Operating Procedures (SOPs) and/or Rules of Engagement (RoEs), exchanges of tactical/strategic information, existence of an umbrella platform dealing with political issues and communication in the name of the members of the ‘coalition’, facilitating military operations of one of the actors in the areas under control of another actor, coordinating simultaneous attacks against the common enemy, conducting joint operations, etc.

A shared ideology, similarities of political views or the mere existence of a common enemy would not constitute sufficient grounds for concluding that different parties are fighting under the framework of a coalition. These may be elements to factor in but, alone, would not be enough to justify the aggregation of intensity for the purpose of legally classifying a NIAC.

Should the analysis fall short of sufficient elements to conclude that armed actors are pooling military resources to fight a common enemy, the intensity criterion should not be addressed collectively in order to determine the existence of a new NIAC between these groups and their enemy. Without a form of coordination of military action, IHL would require observing that each bilateral relationship of violence satisfies the intensity criterion. This would potentially lead to classification of several, distinct NIACs for some of the situations, while others would fall short of IHL application.

However, if the analysis concludes that there are enough elements to consider several armed actors to be operating in a coalition, to determine whether the situation amounts to a new NIAC – and moving away from the aforementioned strict fragmentation approach to examining the level of intensity under these specific circumstances – it could be argued that the intensity criterion be observed from a collective perspective by aggregating the military actions carried by each organized armed actor forming part of the coalition.

Legally sound and practically operative

The main philosophy behind this reasoning is to ensure that the adequate legal framework, which reflects realities on the ground, applies to the situation. It would be unrealistic to expect that governments respond to high-intensity violence against several organized armed groups operating together only with law enforcement measures, as they would probably not be adequate nor adapted. Ultimately, applying IHL to the use of force in such circumstances would therefore also lead to the protection of all the persons who are not, or no longer fighting in these situations, and limit the effect of the violence on the civilian population as a whole.

By applying this logic, among other things, we would also avoid unrealistic expectations under which States would operate under different paradigms – either the law-enforcement or the conduct-of-hostilities paradigm – to respond to the different organized armed groups that operate together against them.

Jann K. Kleffner expressed a similar idea in his Reflections on the Temporal Scope of NIAC, claiming that in the complex situations where ‘the exigencies of the factual situation as requiring – in both humanitarian and military terms – the application of the law of NIAC’, the cumulative approach to intensity should be applied.[11] While Kleffner caveats the application of this approach to a ‘geographical and temporal continuum’, here it is argued that the aggregation of intensity is only considered when armed actors clearly operate in some sort of a coalition, as described above. Nevertheless, Kleffner’s reflections demonstrate that the realities on the ground require that in some circumstances military efforts of different armed groups should be combined for the purposes of assessing the intensity criterion. Expanding on the recent ICRC’s Challenges Report, we suggest an approach, open to debate, that seems most legally sound and practically operative.

In essence, the approach of aggregating intensity facilitates determining the applicable law when facts on the ground suggest that a number of different organized armed actors – be they States or non-State armed groups[12] – are operating together by pooling and marshalling military resources with the view to combating the same enemy. This in turn provides for the protection of civilians, detained persons and others who find themselves in need of protection under IHL. In our view, this approach should in no way be considered as being aimed at diminishing the importance of the intensity criterion. It rather simply constitutes another way to assess and interpret this IHL precondition in light of the contemporary features of NIACs.

See also

[1] Jama’at Nusrat al-Islam wal-Muslimin (JNIM), which is composed of Ansar Dine, Al-Qaeda in the Islamic Maghreb (AQIM) and Al-Murabitoon. See notably RULAC analysis ‘Mali: Several Non-International Armed Conflicts with Various Insurgent Groups’ at http://www.rulac.org/browse/conflicts/non-international-armed-conflits-in-mali.

[2] See ICRC’s operational update of 17 June 2012 at https://www.icrc.org/en/doc/resources/documents/update/2012/syria-update-2012-07-17.htm. Also RULAC analysis ‘Non-international armed conflicts in Syria’ at http://www.rulac.org/browse/conflicts/non-international-armed-conflicts-in-syria#collapse1accord.

[3] See IRRC No. 900,  “The evolution of warfare”, November 2016 at https://international-review.icrc.org/reviews/irrc-no-900-evolution-warfare

[4] For example, according to an ICRC study, although seemingly united as one fighting force, many of today’s non-State armed groups are, in fact, joining forces in some sorts of coalitions. See ICRC, The Roots of Restraint in War, 2018, p. 24; available at https://www.icrc.org/en/publication/roots-restraint-war

[5] The term coalition is used here to reflect the situations when an armed conflict involves, at least on one side, two parties or more fighting together based on the facts on the ground. This also includes situations when new parties join a pre-existing NIAC over time. In this type of situations, the ICRC has suggested to use the so-called “support-based approach”, which will not be discussed in this blog. See Tristan Ferraro, “The ICRC’s legal position on the notion of armed conflict involving foreign intervention and on determining the IHL applicable to this type of conflict” and Tristan Ferraro, Military Support To Belligerents: Can The Provider Become A Party To The Armed Conflict? in 2018 Proceedings of the Bruges Colloquium, “Legal and Operational Challenges Raised by Contemporary Non-International Armed Conflicts”.

[6] See ICRC, Commentary on the Article 3, First Geneva Convention: Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field, 2nd ed., Geneva, 2016, para 386.

[7] ICRC, Commentary on the Article 3, First Geneva Convention: Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field, 2nd ed., Geneva, 2016, paras 421–437

[8] See https://www.icrc.org/en/doc/resources/documents/update/2012/syria-update-2012-07-17.htm

[9] For a detailed analysis of this criterion, see ICTY, The Prosecutor v. Fatmir Limaj, Judgment, IT-03-66-T, 30 November 2005, para. 94-134. This blog is however not focusing on the challenges related to the organization criterion.

[10] ICRC, “International humanitarian law and the challenges of contemporary armed conflicts. Recommitting to protection in armed conflict on the 70th anniversary of the Geneva Conventions”, Geneva, October 2019, submitted to the 33rd International Conference of the Red Cross and Red Crescent, Geneva, Switzerland, 33IC/19/9.7, p. 40-41

[11] Jann K. Kleffner, “The Legal Fog of an Illusion: Three Reflections on “Organization” and “Intensity” as Criteria for the Temporal Scope of the Law of Non-International Armed Conflict”, 95 International Law Studies 161 (2019), p. 172-177

[12] Even though the blog focuses on situations of coalitions formed by non-State armed groups, legally speaking, we do not see any legal arguments under IHL that could preclude the applicability of the approach based on the aggregation of military actions to States coalescing with others States and/or NSAG(s) in order to fight NSAG(s).