A man covers the body of a man killed when gunfire followed a roadside bombing of a joint US and Iraqi patrol in eastern Baghdad, 21 May 2008

Iraqi police say at least 11 people have been killed by gunfire after a roadside bombing near Sadr City, a Shi'ite militia stronghold in Baghdad.

Local officials say the gunfire erupted Wednesday after roadside bombs exploded near a joint U.S.-Iraqi patrol in the Obeidi neighborhood.  The U.S. military, however, says none of its troops were involved.

Sadr City itself remained calm, a day after some 10,000 Iraqi troops began an operation aimed at bringing government control over the Shi'ite stronghold.

The operation is in line with a truce reached earlier this month between Iraq's government and Shi'ite militiamen loyal to radical cleric Moqtada al-Sadr.

Fighting in Sadr City has killed hundreds of people since late March, when Iraqi Prime Minister Nouri al-Maliki ordered a crackdown on Shi'ite militias.