Baghdad ? Iraqi security forces battled Shiite gunmen south of Baghdad on Friday, raising tensions among rival factions of the country’s majority religious community and straining a seven-month cease-fire proclaimed by the biggest Shiite militia.

Also Friday, an American soldier was killed and four others were wounded in a rocket or mortar attack south of the capital, the military said. At least 3,993 members of the U.S. military have died since the beginning of the war five years ago, according to an Associated Press count. The statement did not provide more details about the location; the area has a volatile mix of Sunni and Shiite extremists.

The fighting in Kut, 100 miles southeast of Baghdad, broke out Thursday night when factions of the Mahdi Army, led by anti-American cleric Muqtada al-Sadr, attacked checkpoints throughout the city, officials and witnesses said.

Two policemen and two gunmen were killed during the clashes in Kut, which ended Friday.