US and Iraqi troops killed 30 suspected Shi'ite militiamen late yesterday in the southern Iraqi city of Diwaniya in heavy clashes that police said went on into Sunday.
The US military said the militants were killed after their forces had responded to an attack with rocket-propelled grenades as they entered the Shi'ite city to carry out "combat operations" on Saturday.
US troops have maintained a large presence in the area since a battle in late August in which Shi'ite militiamen killed at least 30 soldiers.
Police said the clashes were between militiamen loyal to Shi'ite cleric Moqtada al-Sadr and US forces. An official in Sadr's office said the US broke a previous agreement by entering the city and hinted they were not involved in clashes.
"US forces broke the agreement we agreed ... that they do not enter the centre of the city and gunmen clashed with them. Moqtada al-Sadr has prevented us from fighting the Americans in Diwaniya," he said on condition of anonymity.
The operation follows a swoop by thousands of Iraqi police and soldiers in the oil city of Kirkuk, yesterday.
Homes were searched for weapons and insurgents after all residents were ordered off the streets.
In northern Tal Afar, northwest of Kirkuk, a suicide car bomber killed 14 people in an attack on an Iraqi army checkpoint, the latest in a series of deadly suicide bombings in the town since the start of the Muslim holy month of Ramadan.
The bloodshed followed a warning by US Senate Armed Services Committee Chairman John Warner that Iraq's government had 60 to 90 days to control the violence that threatens civil war or the United States would have to reconsider its options.
Meanwhile, Iraqi Prime Minister Nuri al-Maliki held talks with Sunni tribal leaders and announced plans for reconstruction projects and more representative local government in Anbar province, heartland of the Sunni insurgency. The region north of Baghdad has also seen a surge of violence.
Kirkuk, 155 miles north of Baghdad, is an ethnically mixed city claimed by Arabs, Kurds and Turkmen which has seen an upsurge of violence. A spate of near simultaneous car bombs in the city killed more than 20 people on September 17 th.