Aiming attacks at civilians, regardless of the circumstances, is a "grave breach," a war crime, under international humanitarian law, and the perpetrators are subject to individual criminal prosecution. B'Tselem calls on the Palestinian Authority to impose its authority on the bodies engaged in firing rockets at Israeli communities, and to meet its obligations to prevent attacks against civilians. International humanitarian law requires the PA to take urgent and vigorous action to achieve this objective.
Israel has the right and obligation to protect its citizens. however, acts of vengeance are forbidden by international law.