A "free fire" policy towards infiltrators was adopted—a policy of shooting those crossing the international armistice line illegally. Eventually, the Israeli leadership came to the conclusion that only retaliatory strikes would be able to create the necessary factor of deterrence, that would convince the Arab armies to prevent infiltration. Although the strikes were sometimes confined to military targets (particularly, at the later stages of the infiltration), numerous civilians were killed, prompting the question whether the strikes were a form of collective punishment[citation needed].