At least three people have been killed in a car bomb attack in the Iraqi capital, Baghdad, as U.S. and Iraqi troops continue an offensive against insurgents in the west of the country.

A U.S. soldier removes a hat and cardboard box from a damaged SUV, after a roadside bomb detonated next to an American military convoy guarded by two Humvees in eastern Baghdad

Authorities say Thursday's attack targeted a police patrol in northern Baghdad's popular Shula district. They say at least two policemen and one civilian were killed in the attack.

The latest violence came as more than one thousand U.S. and Iraqi troops continued their search for insurgents loyal to Abu Musab al-Zarqawi in the western city of Haditha, in al-Anbar province. U.S. officials say 10 suspected insurgents have been killed and two U.S. Marines wounded in Operation New Market.

The operation is the second major offensive in al-Anbar province this month.