In a Non-International Armed Conflict the rules are not clear, because there are usually not organised armed forces involved in the fighting. Treaty provisions governing Non-International Armed Conflict do not use the term combatants and the Manual for Non-International Armed Conflict uses the term 'fighters'.
Fighters: a. For the purposes of this Manual, fighters are members of armed forces and dissident armed forces or other organised armed groups, or taking an active (direct) part in hostilities. b. Medical and religious personnel of armed forces or groups, however, are not regarded as fighters and are subject to special protection unless they take an active (direct) part in hostilities.
It is evident that members of organised armed forces can be targeted at any time. However, with many of the victims of drone attacks it is unclear whether the ‘militants’ are actual members of armed forces or an organised armed group.
DISCUSSION PAPER 2: DRONE ATTACKS, INTERNATIONAL LAW, AND THE RECORDING OF CIVILIAN CASUALTIES OF ARMED CONFLICT, p. 14