MOSUL, Iraq, Oct. 12 (Xinhua) -- Two bomb attacks targeting U.S. and Iraqi troops on Sunday killed seven people here, a provincial police source said.

    A suicide bomber detonated explosives on his car at about 6 p.m. (1500 GMT) in an western district of the city, the source said, adding that the blast apparently was targeting a U.S. patrol.

    The explosion killed five Iraqi civilians and wounded 14. It was not immediately clear whether the American troops sustained casualties.

    Two policemen died and another two were injured in a car bombing more than one hour later in the Zanjili district.

    Mosul, some 400 km north of Baghdad, is still susceptible to frequent violence amid a security upturn in most of Iraq.

    About 1,000 Christian families in the city have been displaced since late September in a latest wave of violence against them, according to police and church sources.

    Iraqi Prime Minister Nuri al-Maliki vowed Sunday to take steps to protect Christians in Iraq.