International law contains a system of rules referred to as the "laws of war." These rules establish the red lines that a combatant or occupying state may not cross. Among the instruments in which the rules are stated are the Hague Convention of 1907 and its regulations, and the four Geneva Conventions of 1949.
The principal concept of the Humanitarian Law is that, even in wartime, all acts are not allowed. Humanitarian law does not deal with the question of whether the war is justified, but with the means used during the conflict. For example, the rules limit the parties in order to minimize the harm to non-combatants, such as prisoners of war, the wounded, and civilians. In addition, humanitarian law contains provisions restricting the arms that may be used during the conflict.
The Hague Regulations, which establish the laws for conducting war on land, are considered part of international customary law. The Regulations state the rights and duties of the combatants, and limit the means to injure the enemy. Among their provisions are the duty of the occupying state "to ensure public order and safety" in the occupied territory and the prohibition on collective punishment of the civilian population. The Regulations also forbid expropriation of property of residents of the occupied territory.
The four Geneva Conventions for the protection of victims of war of 1949, and its protocols of 1977 comprise the major part of humanitarian law applying to war and occupation. Israel signed the conventions but not the protocols.
The First Geneva Convention deals with the wounded, sick, medical teams, and military religious personnel. The Second Geneva Convention deals with war at sea. The Third Geneva Convention deals with prisoners of war.
The Fourth Geneva Convention deals with the protection of civilians during war or under occupation, and therefore relates to Israel's actions in the Occupied Territories. The Convention prohibits, among other things, violent acts against residents of occupied territory, the taking of prisoners, injury to the dignity of civilians, acts of retaliation against them, collective punishment, and mass or individual deportation. The Convention also protects children by ensuring maintenance of relations between family members who have been separated as a result of war, protects property, provides safeguards for detainees and prisoners, and states many other protections. The Convention also sets due process standards for criminal trials conducted against residents of occupied territory and prohibits occupying states from settling its citizens in occupied territory.