Special report: Tension escalates in Iraq

    BAGHDAD, April 3 (Xinhua) -- U.S. troops killed five Iraqi policemen and wounded 11 people during a predawn military operation in the city of Hilla, 100 km south of Baghdad, a city police source said on Thursday.

    The incident took place when U.S. troops entered the Jamiyah district in central of the city, and clashed with policemen guarding the building of the governor office, the source told Xinhua on condition of anonymity.

    The source said a guard of the office opened fire on the U.S. troops mistakenly and the troops fired back and killed him.

    A police force based in a nearby headquarters opened fire on the U.S. troops, thinking they were militiamen, sparking a fierce clash, he said.

    A U.S. helicopter involved in the clashes and pounded the area,killing four more policemen and wounding nine others, the source said.

    Two more women were wounded by the air strike, which also caused damages to nearby houses and destroyed parts of a police headquarters and several police vehicles, he said.

    The U.S. military said its troops were on an operation to detain a member of Mahdi Army militia, loyal to radical cleric Muqtada al-Sadr.

    A military spokesman said that three civilians were injured, several buildings were damaged and one vehicle was destroyed during the clash.

    The building of the governor office was targeted by gunmen attacks and mortar rounds during the recent battles between the U.S.-backed Iraqi security forces and Mahdi Army militia in several Iraqi southern cities.