The bomb exploded early Friday morning about 200 meters from a mosque in the New Baghdad district, southeast of the capital.

Most of the civilian casualties were aboard a minibus, which was near a three-vehicle U.S. military convoy when the blast occurred. Blood covered the seats and the floor of the badly damaged bus.

A local shopkeeper, Basim Ibrahim, says he was standing outside his store when he saw the military convoy slowing down for a red light. He says a remotely detonated bomb suddenly ripped through one of the U.S. Humvee vehicles and the mini bus.

Mr. Ibrahim says the bomb hit the third Humvee in the convoy. He says the driver of the vehicle appeared to have been killed instantly.

The U.S. military confirms that one soldier was killed in the incident.

The explosion was so powerful, it blew out the windows of surrounding buildings and uprooted a tree. Many Iraqis, who were on their way to the al-Samarrai mosque for Friday prayers, expressed dismay at the latest violence. They say they do not understand why the insurgents are killing innocent civilians.

The attack came ahead of a visit here by U.S. Secretary of Defense Donald Rumsfeld on Friday. He was scheduled to meet U.S. administrator Paul Bremer and other coalition officials.