A car bomb blast near an Iraqi police patrol in southern Baghdad killed 10 people today and wounded nearly a dozen, the US military said.
Earlier reports said only one person had been killed in the attack in the Dora neighbourhood of southwestern Baghdad.
The US military said the car, packed with about 300 pounds of explosive went off this morning as an Iraqi police patrol was passing. All of those killed were civilians, including a family of four travelling in a car.
Overnight US warplanes bombed targets in Iraq's rebel-held city of Fallujah, marking a violent start to the holy Muslim fasting month of Ramadan.
US marines, soldiers and Iraqi forces stepped up security operations in and around Fallujah on last night to disrupt planned attacks by insurgents, the US military said.
Washington and Baghdad have vowed to retake insurgent-held towns and cities ahead of nationwide elections due in January.
There was no immediate word on casualties in the overnight raids, which the military said were aimed at Jordanian militant Abu Musab al-Zarqawi.
Zarqawi's group said it was behind twin suicide bombings that killed five people, three of them Americans, in the heart of Baghdad's heavily fortified Green Zone yesterday.
The interim government has told the people of Fallujah to surrender Zarqawi and other foreign militants said to be holed up in the city of 300,000 or face military action.
Ramadan, observed by Iraq's minority Sunnis from Friday, will start for the majority Shias on Saturday.