'Deliberately targeting civilians is a grave breach of the fundamental principles of international humanitarian law,' the organisation said. 'This is an unacceptable tragedy and we call on armed Palestinian groups to immediately cease killing civilians.'

'At the same time we remind the Israeli Government that, however shocking the abuses of international humanitarian law by armed groups, the Fourth Geneva Convention on the Protection of Civilian Persons in Time of War prohibits governments from carrying out reprisals against 'protected persons or their property',' Amnesty International added