Unlawful_Combatant

Wikipedia

If civilians directly engage in hostilities, they are considered 'unlawful' or 'unprivileged' combatants or belligerents (the treaties of humanitarian law do not expressly contain these terms). They may be prosecuted under the domestic law of the detaining state for such action"

The Geneva Convention relative to the Treatment of Prisoners of War, 12 August 1949 (GCIII) of 1949 defines the requirements for a captive to be eligible for treatment as a POW. A lawful combatant is a person who commits belligerent acts, and, when captured, is treated as a POW. An unlawful combatant is someone who commits belligerent acts but does not qualify for POW status under GCIII Articles 4 and 5.

Article 4

A. Prisoners of war, in the sense of the present Convention, are persons belonging to one of the following categories, who have fallen into the power of the enemy:

1. Members of the armed forces of a Party to the conflict as well as members of militias or volunteer corps forming part of such armed forces.

2. Members of other militias and members of other volunteer corps, including those of organized resistance movements, belonging to a Party to the conflict and operating in or outside their own territory, even if this territory is occupied, provided that such militias or volunteer corps, including such organized resistance movements, fulfill the following conditions:

(a) That of being commanded by a person responsible for his subordinates;

(b) That of having a fixed distinctive sign recognizable at a distance;

(c) That of carrying arms openly;

(d) That of conducting their operations in accordance with the laws and customs of war.

1. Members of regular armed forces who profess allegiance to a government or an authority not recognized by the Detaining Power.

2. Persons who accompany the armed forces without actually being members thereof, such as civilian members of military aircraft crews, war correspondents, supply contractors, members of labour units or of services responsible for the welfare of the armed forces, provided that they have received authorization from the armed forces which they accompany, who shall provide them for that purpose with an identity card similar to the annexed model.

3. Members of crews [of civil ships and aircraft], who do not benefit by more favourable treatment under any other provisions of international law.

4. Inhabitants of a non-occupied territory, who on the approach of the enemy spontaneously take up arms to resist the invading forces, without having had time to form themselves into regular armed units, provided they carry arms openly and respect the laws and customs of war.

B. The following shall likewise be treated as prisoners of war under the present Convention:

1. Persons belonging, or having belonged, to the armed forces of the occupied country…

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Article 5

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Should any doubt arise as to whether persons, having committed a belligerent act and having fallen into the hands of the enemy, belong to any of the categories enumerated in Article 4, such persons shall enjoy the protection of the present Convention until such time as their status has been determined by a competent tribunal.