Categories of Armed Conflicts in International Humanitarian Law
International humanitarian law applies only when the factual threshold of armed conflict is reached, and the category of conflict determines the applicable treaty regime, status rules, detention rules, and war-crimes consequences. The legal classification depends on objective facts, not on a declaration of war, the terminology used by the parties, the political legitimacy of a cause, or the domestic label of rebellion, terrorism, insurgency, invasion, police operation, or peacekeeping.
For Philippine law, classification matters because the Philippines accepts generally accepted principles of international law as part of the law of the land, is bound by the Geneva Conventions and their relevant protocols, and punishes serious violations through the Philippine Act on Crimes Against International Humanitarian Law, Genocide, and Other Crimes Against Humanity. Domestic security law, criminal law, military regulations, and human rights law continue to operate, but IHL supplies the special rules for hostilities once an armed conflict exists.
Function of Classification
The first inquiry is whether the situation is an armed conflict rather than ordinary criminality, internal disturbance, or law-enforcement violence. The second inquiry is whether the conflict is international, non-international, a war of national liberation treated as international, or a mixed situation containing more than one classification at the same time.
IHL classification is factual and may change over time. A situation may begin as internal unrest, mature into a non-international armed conflict, become internationalized by foreign State intervention, or contain parallel conflicts between different pairs of parties. The same battlefield may therefore involve an international armed conflict between States and a non-international armed conflict between a State and an organized armed group.
| Category | Basic Parties | Threshold | Principal Legal Consequence |
|---|---|---|---|
| International armed conflict | Two or more States | Resort to armed force between States, including occupation | Full law of international armed conflict applies, including combatant and prisoner-of-war concepts |
| Non-international armed conflict | State and organized armed group, or organized armed groups | Organized parties and violence reaching sufficient intensity | Common Article 3, customary IHL, and applicable protocol rules govern minimum humane treatment and conduct of hostilities |
| War of national liberation | People fighting colonial domination, alien occupation, or racist regime | Armed struggle for self-determination within the recognized treaty framework | Treated as international armed conflict under Additional Protocol I |
| Internal disturbance or tension | State authorities and civilians, mobs, gangs, or loosely organized actors | Violence below the armed-conflict threshold | IHL does not apply; constitutional, criminal, human rights, and law-enforcement rules control |
Armed Conflict Threshold
An armed conflict exists when there is resort to armed force between States or protracted armed violence involving organized armed groups. The threshold prevents every riot, police encounter, election-related clash, or isolated terrorist act from being treated as war.
International armed conflict has a low threshold because any hostile use of armed force by one State against another State triggers IHL between them. Non-international armed conflict has a higher threshold because IHL should not displace ordinary internal security law unless the violence and the organization of the parties make hostilities resemble armed conflict.
The assessment is made from the situation as a whole. Relevant facts include the command structure of the armed group, its capacity to conduct coordinated operations, territorial presence, weapons used, frequency and gravity of attacks, number of fighters, military response required, displacement of civilians, and the duration and spread of violence.
International Armed Conflict
An international armed conflict arises when there is armed force between two or more States, even if neither State recognizes a state of war. It includes invasion, bombardment, cross-border attacks, naval or aerial hostilities, and the capture or detention of enemy armed forces.
Occupation is an international armed conflict even if the occupation meets no armed resistance. The controlling fact is the substitution of the authority of the occupying power for the authority of the territorial State over an area, whether the occupation is total or partial.
International armed conflict also includes hostilities between a State and forces whose conduct is legally attributable to another State. Attribution may become important when a foreign State directs, controls, equips, or uses an armed group as its instrument, because the legal relationship between the territorial State and the foreign State may be international even if local fighters are physically carrying out operations.
The category carries the most developed status rules. Members of the armed forces of a party generally have combatant status, may be targeted while participating in hostilities, and may receive prisoner-of-war protection upon capture if the requirements of IHL are met. Civilians are protected against direct attack unless and for such time as they directly participate in hostilities.
Non-International Armed Conflict
A non-international armed conflict is armed conflict not of an international character occurring within a State or across territory without becoming a State-to-State conflict. It usually involves government forces and an organized armed group, but it may also involve sustained hostilities between organized armed groups when the required intensity and organization are present.
Common Article 3 of the Geneva Conventions supplies the minimum humanitarian floor for non-international armed conflict. It requires humane treatment of persons taking no active part in hostilities, including detained fighters, wounded persons, civilians, and those who have laid down their arms, and it prohibits murder, mutilation, cruel treatment, torture, hostage-taking, humiliating and degrading treatment, and sentences or executions without regularly constituted judicial guarantees.
Additional Protocol II applies to a narrower class of non-international armed conflicts involving State armed forces and dissident armed forces or other organized armed groups under responsible command that exercise such control over territory as to enable sustained and concerted military operations and implementation of the protocol. Its threshold is higher than Common Article 3, so a conflict may be covered by Common Article 3 even when Additional Protocol II does not apply.
Non-international armed conflict does not create combatant privilege for members of organized armed groups. They may be prosecuted under domestic law for rebellion, terrorism, murder, illegal possession of firearms, or other offenses, although they remain protected by IHL from torture, summary execution, collective punishment, and attacks that violate the rules on distinction, proportionality, and precautions.
War of National Liberation
A war of national liberation is an armed struggle by a people against colonial domination, alien occupation, or a racist regime in the exercise of the right of self-determination. Under Additional Protocol I, such a conflict is treated as international armed conflict, not merely as an internal conflict.
The category is exceptional. Ordinary secessionist violence, rebellion against a constitutional government, or ideological insurgency does not automatically become a war of national liberation merely because the group invokes self-determination. The classification depends on the internationally recognized context of colonial domination, alien occupation, or racist regime, and on compliance with the treaty framework governing such struggles.
Mixed and Internationalized Conflicts
Modern conflicts often contain several legal relationships. If a foreign State intervenes with its own armed forces against another State, an international armed conflict exists between those States, while a separate non-international armed conflict may continue between the territorial State and an organized armed group.
Foreign assistance alone does not always internationalize a conflict. Training, funding, intelligence support, or weapons transfers may affect responsibility and attribution, but the classification turns on whether a foreign State itself becomes a party to hostilities or whether the armed group acts as a legally attributable organ or instrument of that State.
Peace operations must also be classified by facts. A peacekeeping or multinational force may remain outside the conflict if it performs a neutral mandate without becoming a party to hostilities, but IHL applies to the force once it engages in sustained combat or otherwise becomes a party to an armed conflict.
Situations Below Armed Conflict
Internal disturbances, riots, isolated and sporadic acts of violence, banditry, coup attempts of brief duration, and ordinary counterterrorism or law-enforcement operations do not by themselves constitute armed conflicts. They remain governed by the Constitution, criminal law, rules on arrest and detention, human rights obligations, and police or military rules on the use of force.
The presence of military units does not automatically mean IHL applies. Armed forces may assist in law enforcement without creating an armed conflict if the opposing actors lack organization or if the violence lacks the required intensity.
Conversely, a State cannot avoid IHL by calling a sufficiently intense and organized conflict a police action. Once the factual threshold is reached, the parties are bound by IHL even if the government refuses to recognize the opposing group, refuses belligerency status, or continues to prosecute its members under domestic criminal law.
Legal Effects of Classification
The classification of conflict determines the applicable status of fighters. In international armed conflict, combatant and prisoner-of-war rules are central; in non-international armed conflict, fighters of organized armed groups do not receive combatant immunity, although captured or detained persons must be treated humanely.
The classification also affects the scope of grave breaches and war crimes, but serious violations may be punishable in both international and non-international armed conflicts under Philippine law. The Philippine IHL statute covers serious violations such as intentionally directing attacks against civilians, protected persons, humanitarian personnel, or civilian objects; employing prohibited means or methods of warfare; and committing outrages upon personal dignity and other grave abuses.
Some conduct-of-hostilities principles apply across categories as customary IHL. Parties must distinguish civilians from combatants or fighters, distinguish civilian objects from military objectives, refrain from indiscriminate attacks, observe proportionality, take feasible precautions, collect and care for the wounded and sick, respect medical and humanitarian personnel, and protect persons hors de combat.
Classification does not decide the legality of the resort to force. The law on the use of force determines whether a State may lawfully use armed force; IHL determines how parties must fight once an armed conflict exists. Even an aggressor State and even an unlawful armed group must comply with humanitarian rules, and their enemy must comply as well.
Philippine Context
In the Philippines, internal security situations are not classified by rhetoric but by the organization of the armed group and the intensity of violence. Encounters with criminal groups, private armed groups, or terrorist cells may remain law-enforcement matters unless the actors have sufficient organization and the violence reaches the armed-conflict threshold.
Where a non-international armed conflict exists, the government may still enforce rebellion, terrorism, firearms, and ordinary penal laws, but military operations must comply with IHL. The State's duty to protect civilians, investigate violations, prosecute international crimes, and provide remedies coexists with its authority to suppress insurgency and maintain public order.
Civilian protection is central in all classifications. Civilians are not lawful targets unless and for such time as they directly participate in hostilities; displacement, starvation, hostage-taking, collective punishment, torture, sexual violence, recruitment of children, and attacks on schools, hospitals, and humanitarian relief are governed by stricter humanitarian and criminal-law consequences when connected with armed conflict.
Dispute Resolution and Classification Disputes
Disagreements over classification may arise because parties have incentives to avoid the legal consequences of armed conflict or to deny the status of an adversary. Such disputes do not suspend minimum humanitarian obligations; at the least, humane treatment rules bind parties whenever the factual threshold of armed conflict is present.
Classification disputes may be addressed through diplomatic channels, protecting-power arrangements, humanitarian engagement, fact-finding, domestic courts, international accountability mechanisms, and the work of neutral humanitarian actors. These processes identify the applicable law, support compliance, and preserve accountability, but they do not create the underlying armed conflict; the facts do.
Operational Summary
- International armed conflict is triggered by armed force between States or occupation, regardless of formal declaration.
- Non-international armed conflict requires organized armed parties and violence of sufficient intensity.
- War of national liberation is treated as international armed conflict only within the recognized self-determination contexts covered by Additional Protocol I.
- Internal disturbances and isolated violence remain outside IHL, though human rights, criminal law, and constitutional limits still apply.
- Mixed conflicts require separate classification of each legal relationship between the relevant parties.
- Classification affects status, detention, applicable treaty rules, and war-crimes liability, but core humanitarian protections apply across armed-conflict categories.