Special report: Tension accelerates in Iraq     

    BAGHDAD, March 22 (Xinhua) -- A suicide car bomber struck a U.S. military convoy on the main road leading to Baghdad International Airport on Wednesday morning, an Interior Ministry source told Xinhua.

    "A suicide bomber drove his explosive-laden vehicle into a U.S. military convoy on the airport road in western Baghdad at about 7:30 a.m. (0430 GMT)," the source said on condition of anonymity. It was not clear whether there were any casualties among the U.S. troops as the U.S. forces cordoned off the scene, preventing Iraqi police from approaching the area, the source said.

    Insurgents frequently attack U.S. military convoys with roadside bombs and car bombs on the main roads in Iraq, particularly on the most dangerous road in Iraq near the airport in western Baghdad.

    The U.S. military has no immediate comment on the incident. Earlier on Wednesday, insurgents waged a well-planned attack on an Iraqi police base in Madain, some 30 km south of Baghdad with mortars and gunfire, killing a commander of an Iraqi public order battalion and three policemen, a ministry source said.

    "Insurgents pounded a base of the al-Salam public order battalion in Madain area at about 4:00 a.m. (0100 GMT) followed by a machinegun and rocket-propelled grenades attack," the source told Xinhua on condition of anonymity.

    Iraqi security forces in Madain involved in fierce clashes with the insurgents and surrounded the area, detaining some 50 militants, including a Syrian national, he said.

    Wednesday morning's attack against Iraqi police came a day after dozens of insurgents launched another well-planned attack at a police headquarters of Muqdadiya, northeast of Baghdad, killing 18 policemen and wounding nine others. Enditem