Gunmen attacked a large convoy of U.S. troops heading toward Najaf (searchwith gunfire and roadside bombs, killing one soldier and wounding two others and an American civilian contractor, officers in the convoy said Tuesday.

The 80-vehicle convoy was struck late Monday, when a volley of fire erupted north of the city. A roadside bomb hit a truck. The convoy accelerated through the ambush and continued on its way toward Najaf, 100 miles south of Baghdad (search).

The large U.S. force was coming from the north to deploy at Najaf. The U.S. military has vowed to capture a radical Shiite cleric, Muqtada al-Sadr (search), who is in the city and whose militia led a violent uprising against coalition troops across the south last week.