More than 50 people were killed in violence Saturday, many in a gunbattle between Shiite militia forces and insurgents south of Baghdad.

South of the capital, 40 people were killed or wounded in a big gunbattle near Mahmoudiya, police said. Police said gunmen of the Shiite Mahdi Army militia were fighting insurgent forces, which are primarily Sunni Muslim.

Hospital officials reported two civilians were killed when a mortar shell slammed into their house in the town, some 20 miles south of Baghdad.

Elsewhere, a female teacher was killed by Iraqi soldiers as she drove past their convoy, police said. Gunmen also killed a Sunni mosque preachers when he stopped to have his car repaired in west Baghdad.

Earlier, a bomb exploded in a traffic police hut in north Baghdad, killing four civilians. Five people, including a traffic policeman, were wounded in the attack near the Iraqi Finance Ministry, police said.

Three people in a car were killed by gunmen in the northern city of Mosul and two were wounded, one critically police said.

In Balabroz, 55 miles northeast of Baghdad, two men were killed and three wounded when a roadside bomb exploded near a police checkpoint, authorities said.

Iraqi police also found two more bodies, with their hands and legs tied and shots to the head. One was in southeastern Baghdad; the second was floating in the Tigris River, 55 miles south of the capital.

On Friday, at least 51 other people were reported to have died in violence, including two U.S. soldiers killed in western Anbar province.