In Baghdad, a double car bombing struck a busy commercial district, killing 13 people in one of the deadliest attacks in the capital in weeks. Iraqi officials said the explosives-laden cars were parked between a passport office and a courthouse when they blew up almost simultaneously in the mainly Shiite neighborhood of Karradah.

Iraqi woman walks past damage made by two car bombs in a central commercial district of Karrada in Baghdad, Iraq, Monday, Sept. 15. 2008. Police and hospital officials have said the death toll in a double car bombing in Baghdad is at least 12 killed and 36 wounded and dozens of cars were burned or damaged. [Agencies]

Encouraged by security gains, authorities several months ago lifted a ban on parking vehicles in the area that had been imposed to prevent such attacks, although the buildings remained surrounded by concrete walls for protection.

Police and an Interior Ministry official said the dead were civilians. The officials, who spoke on condition of anonymity because they weren't authorized to release the information, said 35 people were wounded and dozens of cars were burned or damaged in the attack.

The US military blamed the Baghdad attacks on al-Qaida in Iraq, which has been severely weakened by military campaigns but retains the ability to carry out devastating strikes. Lt. Gen. Lloyd Austin, the No. 2 American commander in Iraq, said key measures of insurgent violence today are about 80 percent lower than one year ago but cautioned that it would be a mistake to push the US-trained Iraqi army and police into a leading security role before they are ready.

The attacks came as US Defense Secretary Robert Gates arrived in Baghdad to meet Iraqi officials and preside over Tuesday's handover ceremony to mark the transition of command of US forces in Iraq.

Also Monday, Iraq's chief government spokesman said Iraq now needs less foreign aid and funds than in the past and dismissed criticism from some US politicians that Iraq is not sharing enough of the burden of security and reconstruction.

"What we need now is expertise and training program rather than funds," spokesman Ali al-Dabbagh said. "I think it is unreasonable that someone sitting in Washington can talk about this issue, without understanding the volume of difficulties we are facing on the ground here."

In Washington, senators have called for Baghdad to pay more for its own reconstruction, which has been heavily supported by hard-pressed American taxpayers.