[S]oldiers in combat must consider the following to be lawful combatants: members of the armed forces and organized units, franc-tireurs detached from their regular units, commando detachments and isolated saboteurs and members of voluntary militias, self-defence groups and organized resistance movements.

In order for these categories [of persons] to be considered lawful combatants, their units, organizations and groups must have a designated commander and their members must display a distinctive sign, especially on their clothing, carry their arms openly and respect the laws and customs of war.