An Israeli missile is launched from the Iron Dome missile system in response to a rocket launch from the nearby Palestinian Gaza Strip, on March 12, 2012 near Ashdod, Israel. According to the IDF, four rocket-launching sites, militants and a weapons storage facility have been targetted overnight. The Iron Dome has shot down over 40 rockets launched into Israel as Israeli PM Netanyahu pledges to boost civilian defence. The death toll, following four days of conflict, has reached 21. (Photo by Uriel Sinai/Getty Images)

Israeli school girls take cover next to a bus during a rocket attack from the nearby Gaza Strip, on March 12, 2012 in Ashdod, Israel. The UN and EU have appealed for calm as cross border rocket strikes continued into a fourth day between the Gaza Strip and Israel, which have so far resulted in 23 Palestinian deaths. (Photo by Uriel Sinai/Getty Images)

An Israeli man looks out of a window after a rocket attack from the nearby Gaza Strip, on March 12, 2012 in Ashdod, Israel. (Photo by Uriel Sinai/Getty Images)

An Israeli woman is evacuated following a rocket attack from the nearby Gaza Strip, on March 12, 2012 in Ashdod, Israel. (Photo by Uriel Sinai/Getty Images)

Israeli policemen inspect damage after a rocket attack from the nearby Gaza Strip, on March 12, 2012 in Ashdod, Israel. (Photo by Uriel Sinai/Getty Images)