BAGHDAD, Jan 24 (Reuters) - U.S. and Iraqi troops backed by tanks clashed with gunmen in central Baghdad for a second day on Wednesday as helicopters flew overhead, residents said. The U.S. military had no immediate comment on the clashes, which took place on the west bank of the Tigris River in the centre of old Baghdad. It said it was preparing a statement. Two residents told Reuters they had seen a large armoured force of U.S. and Iraqi troops enter Haifa Street, a stronghold of Sunni Arab insurgents, at 6 a.m. (0300 GMT). They said the troops were clashing with gunmen near a cemetery and that U.S. snipers had been deployed on the roofs of some buildings. On Tuesday a private security helicopter came down just across the river, and a U.S. official said five people had been killed. It was not immediately clear whether it had been shot down.
