Shiite fighters and police battled on Friday in the southern Iraqi town of Samawa, while separately roadside bombs killed at least eight Iraqi soldiers, security sources said.
Meanwhile, American forces said they had killed three gunmen in raids in western Iraq.
A Samawa police captain told AFP the fighting had broken out on Thursday when police tried to crack down on armed members of cleric Moqtada al-Sadr's Mahdi Army militia. Fighting was continuing, he said.
Hillal al-Hatchami, an emergency medic at the town's Muthanna Hospital, said at least one policeman and four civilians died in the fighting and 26 people injured.
Meanwhile, further north near the town of Hilla, a roadside bomb hit an Iraqi army patrol on the main route east of town on Friday and killed four troops, according to Lieutenant Haider al-Husseini. Four more members of the security forces, police commandos, died in a similar attack near the ruined Al-Askari shrine in the northern city of Samarra, a local security official told AFP.
At least four more Iraqis died in attacks in the north of the country, according to security officials.
In another development Iraq has executed an Al-Qaeda fighter who carried out one of the first and deadliest bombings in Iraq's bloody sectarian war, an official said Friday. On August 2003, senior Shiite cleric Ayatollah Mohammad Baqer al-Hakim and at least 84 more people were killed when a car bomb went off outside the Imam Ali mausoleum in Najaf, the holiest shrine in Shiite Islam.