U.S. air strikes killed at least 13 people and wounded 52 early on Sunday in the northeastern Baghdad district of Sadr city, a stronghold for Shi'ite militants, two police sources said.

The U.S. military confirmed it had conducted early morning operations in Sadr city "targeting criminals believed to be responsible for the kidnapping of coalition soldiers in November 2006 and May 2007".

The poor district is a stronghold for followers of Shi'ite cleric Moqtada al-Sadr and has witnessed frequent clashes between U.S. forces and militants.

The U.S. commander for Baghdad, Maj. Gen. Joseph Fil, said in September that while security was getting better in some parts of Baghdad following a U.S. crackdown, areas such as Sadr city were likely to continue to see higher violence.

Two polices sources said the death toll was 13, including women and children, and that 52 had been wounded in the strikes. One of the sources said the U.S. raids came after a U.S. vehicle was targeted by a roadside bomb.

"I don't yet have details on the number of terrorists killed, but I can say that we don't have any evidence of any civilians killed or wounded," said a spokesman for U.S. forces.

"Coalition forces only engage hostile threats and make every effort to protect innocent civilians."

One of the police sources said the strikes left several houses, shops and cars ablaze.

A health ministry source said 10 bodies and 42 wounded had been taken to Imam Ali hospital in Sadr city while another body and 25 wounded had been received at a second hospital there.

PHOTO CAPTION

An Iraqi boy plays with his toy gun as US soldiers watch. Fierce fighting between the US military and militants killed at least 13 people and wounded more than 40 early on Sunday. (AFP)

Reuters