Related Rule
Belgium
Practice Relating to Rule 145. 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.
Belgium’s Law of War Manual (1983) states that, when recourse is made to reprisals, the following conditions must be fulfilled: “2) attempts must first be made to stop [the violation of the LOAC by the adversary] or to prevent its repetition by peaceful means”. 
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.
Belgium’s Law of War Manual (1983) states that, when recourse is made to reprisals, the following conditions must be fulfilled: “3) the damage suffered by the adversary must be proportionate to the damage that he has caused”. 
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.
In 1967, a Belgian Senator stated with respect to bombardments of North Vietnam by the United States: “It is recognized today that [reprisals] must be proportionate to the injury suffered. In case one has not suffered any damage, as it was the case, it is incomprehensible to pretend to start a period of bombardments on North Vietnam, as reprisals for attacks on the high sea.” 
Belgium, Parliamentary Debates, 30 November 1967, Annales Parlementaires, Senate, p. 95, reprinted in RBDI, Vol. 6, 1970, pp. 656–657.
Belgium’s Law of War Manual (1983) states: “Although no precise rules exist on the subject, reprisals may only be ordered by the government or commanders-in-chief, because of the importance of the political and/or military consequences they may entail.” 
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.
Belgium’s Law of War Manual (1983), regarding the circumstances in which reprisals may be taken against individuals, cites a writer’s opinion and states: “Putting to death innocent persons to impose order by terror is a violation of both written law and the basic principles of humanity.” 
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. 36, referring to Lord Wright, BYIL, Vol. 25, 1954, p. 296–310.