Соответствующая норма
Practice Relating to Rule 5. Definition of Civilians
In 2010, in its Report on IHL and Current Armed Conflicts, Switzerland’s Federal Council stated:
Existing international humanitarian law treats non-State actors in a different manner depending on whether the situation is an international armed conflict or a non-international armed conflict.
In fact, in international armed conflicts, there are two categories of persons, combatants and civilians, the first having the right to take a direct part in hostilities. …
International humanitarian law establishes criteria for the granting of combatant status. It is primarily for members of the armed forces of a party to the conflict but also for members of other militias. For this, combatants must carry their arms openly, be recognisable (generally by a uniform), be under a responsible command and act in conformity with international humanitarian law in their operations.
Persons not falling in this category are civilians. They notably benefit from protection against direct attacks, provided that and as long as they do not take a direct part in hostilities. This participation does not however constitute a violation of international humanitarian law but entails the loss of the protection against attacks granted to civilians. …
In non-international armed conflicts, international humanitarian law does not provide for any particular status of combatant. Non-State actors participating in the conflict are civilians, who are protected against attacks provided that and as long as they do not take a direct part in hostilities. …
The analysis concerning private military and security companies does not fundamentally differ from that concerning other non-State actors. … As a general rule, they must be considered as civilians (independently of the uniform they wear), that is to say they do not have benefit of any combatant privilege and are only authorized by national law to use arms in cases of legitimate defence. 
Switzerland, Federal Council, Report on IHL and Current Armed Conflicts, 17 September 2010, Section 3.1, pp. 6–8.
[footnotes in original omitted]