US and Iraqi forces killed 13 people in firefights and air strikes overnight in eastern Baghdad where security forces have been battling Shiite militiamen for a week, the military said on Saturday.
Among those killed, a US military statement said, were two snipers, two "criminals" firing rocket-propelled grenades, groups firing machine guns and automatic weapons and three men placing roadside bombs.
The US and Iraqi forces hit back with small arms fire, a Hellfire missile fired from an aerial drone and artillery shells blasted from a M1A2 Abrams tank.
US and Iraqi forces have since Sunday been battling militiamen in Sadr City, bastion of the Mahdi Army fighters of radical Shiite cleric Moqtada al-Sadr, and other Shiite areas of eastern Baghdad killing around 90 people.
Tensions have been further inflamed by the killing on Friday in broad daylight after weeky prayers in the shrine city of Najaf of a senior aide to Sadr, Riyad al-Nuri.