NAJAF, Iraq - Fighting broke out today between U.S. soldiers and Shiite militiamen in Kufa - the eighth straight day of clashes that have all but ruined a deal signed last week aimed at ending violence in the holy city.

At least five Iraqis were killed and 11 injured in the skirmishes in Najaf's twin city, a stronghold of radical cleric Muqtada al-Sadr, hospital officials said. Smoke rose over the dun-colored, flat-roofed houses of the city 100 miles south of Baghdad.

Fighting has rocked Kufa since Shiite leaders announced May 27 that al-Sadr had agreed on a formula to end the confrontation with the Americans in Najaf and Kufa, which together contain some of the most sacred shrines in Shia Islam.

However, the Army has retained the right to mount armed patrols, which al-Sadr's militia, the al-Mahdi Army, considers a provocation. The Americans are reluctant to stop patrols until an Iraqi force is ready to assume security responsibility. Most of the police deserted after al-Sadr launched his rebellion in April.

CNN, which has a correspondent embedded with the 1st Armored Division in the area, said the fighting began after about 100 U.S. soldiers rolled into the center of Kufa early today in search of militiamen who had fired mortar rounds at an American base between Najaf and Kufa.

CNN quoted U.S. officials as estimating that about 30 militiamen were killed. Four American soldiers were lightly wounded. CNN said troops found several rounds of mortars, rocket-propelled grenades and rifles hidden in a school in Kufa.

Although Najaf is relatively quiet, daily clashes in Kufa have rendered the truce almost meaningless. The Americans, who consider al-Sadr a gangster, have refused direct negotiations with him but have agreed to halt "offensive operations."