Palestinian Prime Minister Mahmoud Abbas said that Israel's killing of a top Hamas leader on Thursday would undermine Palestinian efforts to crackdown on militant groups. Israeli helicopters fired five missiles at a car in the Gaza Strip, killing Hamas leader Ismail Abu Shanab and two of his bodyguards. Speaking to reporters outside his office in the West Bank town of Ramallah, Abbas condemned the killing. "There is no doubt that what the Israeli troops carried out today is an ugly crime," he said. "We condemn such acts. This is against peace and the peace process." A faltering, U.S.-backed peace plan...