Соответствующая норма
Practice Relating to Rule 1. The Principle of Distinction between Civilians and Combatants
Section A. The principle of distinction
Nigeria’s Military Manual (1994) states: “The main aim for all commanders and individual combatants is to distinguish combatants and military objectives from civilian persons and objects at all times.”
According to the Report on the Practice of Nigeria, it is Nigeria’s opinio juris that the principle of distinction between combatants and civilians is part of customary international law. 
Report on the Practice of Nigeria, 1997, Chapter 1.1.