US troops clashed with Shi'ite militiamen south of Baghdad on Saturday in a three-hour gun battle in which 15 gunmen and an Iraqi soldier were killed, US officials and Iraqis said. Dozens were wounded in the firefight in Musayyib, about 70 kilometers (40 miles) south of Baghdad. It appeared the battle was part of a systematic campaign against the militia of radical Shi'ite cleric Muqtada al-Sadr, blamed for much of the sectarian violence sweeping the country. Sheik Jalil al-Nouri, an aide to al-Sadr, said US troops attacked the cleric's local office in Musayyib and killed 14 of his followers. A US statement said 15 gunmen and one Iraqi soldier were killed but made no mention of the Mahdi militia.