Iraqi soldiers talk to  woman as she leaves through checkpoint from Shi'ite enclave of Sadr City, Baghdad, 8 Apr 2008

The U.S. military says coalition forces killed at least 13 militants early Saturday in fighting in Baghdad's Sadr City.

The military says U.S. and Iraqi forces battled fighters who attacked with rocket-propelled grenades, machine guns, rifles and roadside bombs.

The joint forces say they used a missile from a drone aircraft and tank fire against the militants.

Iraqi police say seven civilians were killed in the fighting. Military officials say there were no casualties among the U.S. or Iraqi soldiers.

Despite Saturday's battles, authorities eased a blockade on Sadr City, a stronghold of Shi'ite cleric Moqtada al-Sadr's Mahdi Army militia, where coalition forces have been fighting militants for the last two weeks.

Also, a curfew imposed in the southern Iraqi city of Najaf has been lifted one day after Riyadh al-Nouri, Sadr's senior aide, was gunned down near his home.

Tensions between Sadr's militia and U.S.-backed Iraqi government forces erupted into violence when Prime Minister Nouri al-Maliki ordered a crackdown on Shi'ite militias in the southern city of Basra last month.

Elsewhere, Iraqi soldiers uncovered at least four more bodies buried in a field south of Baghdad. Authorities have so far uncovered about 40 bodies from a mass grave in the area. The bodies are believed to have been buried for more than a year.

Meanwhile, the U.S. military says an American soldier was killed Saturday in a roadside bombing near Baghdad, raising this week's U.S. death toll to at least 13.

Some information for this report was provided by AFP, AP and Reuters.