WASHINGTON, June 14 (Reuters) - Seeking to calm sectarian passions in Iraq inflamed by the bombing of a revered Shi'ite shrine, U.S. President George W. Bush urged Iraqis on Thursday to "reject this provocation." Bush spoke after three Sunni Muslim mosques were torched south of Baghdad in apparent acts of reprisal for Wednesday's attack at Samarra's al-Askari mosque that toppled two golden minarets. Addressing a business group in Washington, Bush reiterated the U.S. view that the Samarra bombing "had all the hallmarks of al Qaeda." An attack on the same mosque in February 2006 unleashed waves of sectarian violence in which tens of thousand of people were killed, tipping Iraq close to all-out civil war. The latest bombing raised fears of similar retaliatory violence. "These killers hope that their attacks like this one will create enough confusion and chaos that we will abandon this young democracy," Bush said. "I call on Iraqis to reject this provocation." Bush insisted once again that it is too early to judge the results of a U.S. troop buildup and security crackdown in Baghdad, and said the summer would be a "critical period." With the unpopular war driving down his public approval ratings and facing growing opposition in Congress, he is under increasing pressure to show progress in Iraq. But Bush again warned of a tough road ahead. "We can expect heavy fighting in coming weeks," he said. "We can expect more casualties, both American and Iraqi casualties."
