According to the principle of equality of belligerents, IHL applies equally to all parties to an armed conflict and imposes the same obligations on them.

 OUTLINE

Chapter 2. II. 2. c) aa) Equality of belligerents before IHL

See also Chapter 12, Who is bound by the Law of NIAC  

 LEGAL SOURCE

PI, 96/3(c)

 CASES

UK and Australia, Applicability of PI (B)

Bosnia and Herzegovina, Constitution of Safe Areas in 1992-1993

United States of America, Holder v. Humanitarian Law Project

ICRC, International Humanitarian Law and the challenges of contemporary armed conflicts in 2015 (para. 76)

United Kingdom, The Case of Serdar Mohammed (Court of Appeal and Supreme Court Judgments)

Eastern Ukraine: Disputed POW Status

US, Combatant Immunity and Recognition of belligerency

 BIBLIOGRAPHIC RESOURCES

MEYROWITZ Henri, Le principe de l’égalité des belligérants devant le droit de la guerre, Paris, Pedone, 1970, 418 pp.   ROBERTS Adam, “The Equal Application of the Laws of War: A Principle under Pressure”, in IRRC, Vol. 90, No. 872, December 2008, pp. 931-962   SOMER Jonathan, “Jungle Justice: Passing Sentence on the Equality of Belligerents in Non-International Armed Conflict”, in IRRC, Vol. 89, No. 867, September 2007, pp. 655-690.