Règle correspondante
Practice Relating to Rule 145. Reprisals
Section A. Definition and purpose of reprisals
Belgium’s Law of War Manual (1983) states:
Belligerent reprisals are actions which in themselves are contrary to the law of armed conflict but which are taken in response to violations committed by the adversary and to oblige him to comply with the law of armed conflict.
It adds that, when recourse is made to reprisals, “the following conditions must be fulfilled: 1) the adversary must have committed a violation duly established by the law of armed conflict”. 
Belgium, Droit Pénal et Disciplinaire Militaire et Droit de la Guerre, Deuxième Partie, Droit de la Guerre, Ecole Royale Militaire, par J. Maes, Chargé de cours, Avocat-général près la Cour Militaire, D/1983/1187/029, 1983, p. 35.