Just War Theory - Criteria of Just War Theory - Jus in Bello

Once war has begun, just war theory (Jus in bello) also directs how combatants are to act or should act:

Distinction
Just war conduct should be governed by the principle of distinction. The acts of war should be directed towards enemy combatants, and not towards non-combatants caught in circumstances they did not create. The prohibited acts include bombing civilian residential areas that include no military targets and committing acts of terrorism or reprisal against civilians. Moreover, combatants are not permitted to target with violence enemy combatants who have surrendered or who have been captured or who are injured and not presenting an immediate lethal threat.
Proportionality
Just war conduct should be governed by the principle of proportionality. An attack cannot be launched on a military objective in the knowledge that the incidental civilian injuries would be clearly excessive in relation to the anticipated military advantage (principle of proportionality).
Military necessity
Just war conduct should be governed by the principle of minimum force. An attack or action must be intended to help in the military defeat of the enemy, it must be an attack on a military objective, and the harm caused to civilians or civilian property must be proportional and not excessive in relation to the concrete and direct military advantage anticipated. This principle is meant to limit excessive and unnecessary death and destruction.
Fair treatment of prisoners of war
Enemy soldiers who surrendered or who are captured no longer pose a threat. It is therefore wrong to torture them or otherwise mistreat them.
No means malum in se
Soldiers may not use weapons or other methods of warfare which are considered evil, such as mass rape, forcing soldiers to fight against their own side or using weapons whose effects cannot be controlled (e.g. nuclear weapons).

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