A US soldier died in a blast in Baghdad, hours after three troops were killed in the central Iraqi city of Karbala. "This morning at 7:50 am one military policeman from the 220th Military Police Brigade was killed and two others were wounded in an improvised explosive device in the Baghdad area," a coalition spokeswoman told AFP on Friday. The troops and Iraqi police came under attack by bodyguards of a local cleric in Karbala, 110 kilometers south of Baghdad, the coalition said. Spokesmen said two Iraqi policemen were killed and another five wounded, though the officer who headed the police patrol put the toll among his men at one dead and one wounded, and said the gunmen also suffered several casualties. "Three coalition troops were killed and seven wounded," said US military spokesman Lieutenant-Colonel George Krivo. "The firefight was initiated by non-compliant forces after someone reported that a number of men were congregating with arms near the Al-Abbas mosque after curfew," he said. Witnesses said the fighting occurred outside the residence of local cleric Mahmud al-Hassani, a few hundred meters (yards) from the mosque in Karbala. "We believe that the bodyguards of Hassani were involved. We don't know whether he is personally involved," said Krivo, adding that the assailants used small arms and rocket-propelled grenades. Major Ralph Manos, a spokesman for the multinational force patrolling the Karbala area, said between 20 and 30 assailants were involved in what he called an "unprovoked attack" shortly before midnight Thursday. One of the bodyguards, Bashir Abu Ali, 42, said eight of his comrades were killed in the fighting. Polish coalition troops surrounded the cleric's house on Friday afternoon. The coalition imposed an overnight curfew in Karbala following clashes this week between followers of fundamentalist cleric Moqtada Sadr and other Shiites that left at least one person dead and two dozen wounded. Manos said Hassani's men "were among the parties that took part in the clashes on Monday night among local forces." In a separate incident, a US soldier was seriously wounded Friday near the flashpoint town of Fallujah, 50 kilometers (30 miles) west of Baghdad, when his convoy was hit by an explosive device, a witness said. There was no immediate confirmation from the US military. American tanks remained in position on a main avenue of Sadr City, a sprawling Shiite district where Sadr draws most of his support. **PHOTO CAPTION*** Iraqi fighters muster forces during a gun battle against U.S.-led forces in the streets of Karbala, 110 kilometers south of Baghdad Friday Oct. 17, 2003. (AP Photo/Greg Baker)