I don't need to go to wiki, read the law from the link I posted:
The rules of LOAC provide some protections for civilians, but civilians can lawfully be killed in war. The LOAC principle of distinction prohibits attacks directed against civilians, meaning it is unlawful to intentionally target civilians. Civilians, however, may be incidentally harmed or killed in attacks directed at military objectives. The LOAC principle of proportionality only prohibits attacks against military objectives if the attack is expected to cause incidental harm to civilians or civilian objects that would be excessive in relation to the concrete and direct military advantage anticipated. Thus, the principle of proportionality implicitly authorizes the knowing or foreseeable (but not intentional) killing of civilians in certain circumstances. Indeed, the ratio of civilian to combatant deaths has increased over the past century, particularly with the advent of aerial warfare, the development of more destructive weapons, and the urbanization of societies.