Shiite militiamen attacked a U.S. convoy in southern Iraq, killing two soldiers and setting vehicles on fire, even as mediators were trying Sunday to find a resolution to the U.S. standoff with the militia’s leader. Two other American soldiers were killed in Baghdad. American hostage Thomas Hamill was found by U.S. forces south of Tikrit Sunday after he apparently escaped from his captors, the U.S. military said. Hamill, 43, of Macon, Miss., had been held since an April 9 attack on a convoy. U.S. military units were patrolling a petroleum pipeline when Hamill, a truck driver for a Halliburton Corp. subsidiary, approached and identified himself, said Brig. Gen. Mark Kimmitt. Hamill was in “good health,” Kimmitt said. Full Story