Insurgents opened fire on a U.S. military convoy south of Baghdad (search) on Saturday, apparently causing some U.S. casualties, witnesses said.
Coalition officials in the capital were unaware of the reoprted attack, which occurred in the al-Haswa area, 25 miles south of Baghdad.
Iraqis opposed to the U.S. occupation make daily attacks against coalition troops in Iraq. Since the war began March 20, 546 American service members have died. Most of the deaths have occurred after President Bush declared an end to active combat on May 1.