Three US soldiers were killed Sunday in a bomb attack northwest the Iraqi capital, Baghdad, the US army said. It added in a statement the three troops were killed when a bomb went off near their vehicle. The statement gave no further details nor about the exact location of the attack.Meanwhile, an unknown armed group destroyed a police building in southern Baghdad. A statement by the Iraqi cabinet said a "terrorist group" bomb the building, currently under construction, in the Yousefia area. The statement did not say if the attack caused human casualties.