Соответствующая норма
Practice Relating to Rule 145. Reprisals
Section C. Proportionality of reprisals
Togo’s Military Manual (1996) states that reprisals “may only be used if: … they are proportional to the violation of the law of war committed by the enemy”. 
Togo, Le Droit de la Guerre, III fascicules, Etat-major Général des Forces Armées Togolaises, Ministère de la Défense nationale, 1996, Fascicule III, p. 13.