A non-international armed conflict (NIAC) is the legal category covering most modern wars: civil wars, insurgencies, and conflicts between organized armed groups inside a single state. It is distinguished from an international armed conflict (IAC), which involves two or more states.
Two main treaty sources define NIACs:
- Common Article 3 of the four 1949 Geneva Conventions applies to "armed conflict not of an international character" on the territory of a state party. It sets a humanitarian floor: humane treatment of persons not taking active part in hostilities, prohibition of murder, torture, hostage-taking, and summary executions.
- Additional Protocol II (1977) applies to a narrower set of NIACs — those between a state's armed forces and dissident forces or organized armed groups that exercise control over territory enabling sustained operations.
The threshold for a NIAC, as articulated by the ICTY Appeals Chamber in Prosecutor v. Tadić (1995), requires two elements: (1) intensity of the violence, and (2) organization of the non-state party (responsible command, ability to conduct sustained operations, discipline). Internal disturbances, riots, and sporadic acts of violence fall below this threshold and remain governed by domestic law and human rights law.
Once a situation qualifies as a NIAC, international humanitarian law (IHL) applies in full to all parties, including non-state armed groups. Customary IHL — extensively mapped in the ICRC's 2005 Customary IHL Study — extends many rules originally drafted for IACs (distinction, proportionality, precautions, protection of medical units) to non-international conflicts.
Classification matters: it determines combatant status (there is no combatant immunity in NIACs, so fighters can be prosecuted under domestic law), targeting rules, detention regimes, and the jurisdiction of bodies such as the International Criminal Court under Article 8(2)(c) and (e) of the Rome Statute, which criminalizes serious violations of Common Article 3 and other laws and customs applicable in NIACs.
Example
The conflict between the Colombian government and the FARC, which ran from the 1960s until the 2016 peace accord, was widely classified by the ICRC as a non-international armed conflict.
Frequently asked questions
A NIAC requires sustained, intense armed violence and an organized non-state armed group with responsible command. Riots, protests, and sporadic violence fall below this threshold and are governed by domestic law and human rights law, not IHL.
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