At least five Iraqis, including two policemen and three civilians, were killed when U.S. troops opened fire after their convoy was struck by a roadside bomb at a checkpoint south of Baghdad, police said. The incident happened late Saturday near the police checkpoint in Yussifiyah, 15 kilometers (9 Miles) south of Baghdad, the Interior Ministry spokesman, Col. Adnan Abdul-Rahman, said. The U.S. military said it was investigating the report.