Attackers gunned down an Iraqi contractor who apparently worked with the U.S. military on Sunday, and insurgents fired on a gasoline tanker truck in the southern city of Basra, causing the vehicle to burst into flames. The Iraqi contractor worked for a food services company that had some business at Baghdad International Airport, said an Iraqi police official. He was assassinated Sunday morning by gunmen as he was driving his car on a main road in southern Baghdad, police said. Police in Karbala reported that a suicide car bomber struck a U.S. convoy south of the city Sunday morning, destroying a U.S. vehicle. The U.S. military had no information on the blast, and there was no word on casualties. Also Sunday, an Iraqi civilian was injured by a roadside bomb that exploded but missed an Iraqi police patrol in the southern port city of Basra, police said. Elsewhere in the city, gunmen fired rifle shots at a gasoline tanker truck, and the vehicle exploded into a huge ball of flames. Thick black smoke clouded the area as firefighters directed water hoses at the blaze. No one was hurt in that attack, said police Capt. Mushtaq Talib. The tanker was heading to an illegal port used by oil smugglers in the city, Talib said. In another attack, gunmen fired on a group of Iraqi policemen working to dismantle a roadside bomb on a main street in central Baghdad, injuring two officers, a police official said.