TIKRIT, Iraq, May 6 (Xinhua) -- At least eight people were killed and seven others wounded in two suicide car bomb attacks targeting police headquarters in the city of Samarra, some 120 km north of the capital on Sunday, local police source said.

    "Our first report said that eight people were killed, including the police chief of the city Colonel Abdul Jalil Nahi Hasson, and seven others injured," the source anonymously told Xinhua.

    "The first suicide bomber drove his explosive-laden car into the entrance of the city police directorate and blew it up just as the convoy of the police chief of the directorate was entering the main checkpoint," the source said earlier.

    Elsewhere in the city, a second suicide bomber rammed his explosive-borne car into the police commando headquarters, the source said.

    Authorities of the city imposed curfew again after several hours of lifting previous two-day curfew, the source added. Insurgents frequently attack Iraqi security forces, accusing them of collaborating with the U.S. occupation.