Annex to the Convention: Regulations respecting the laws and customs of war on land - Section I : On belligerents - Chapter I : The qualifications of belligerents - Regulations: Art. 3.
Art. 3. The armed forces of the belligerent parties may consist of combatants and non-combatants. In the case of capture by the enemy, both have a right to be treated as prisoners of war.