Three American soldiers were killed Thursday in a bombing in Baghdad, the U.S. military said, part of a burst of violence only weeks before American combat troops are due to leave Iraqi cities.

The attack was one of a series of bombings to hit Baghdad and the northern city of Kirkuk, killing at least 66 people and wounding dozens more in two days.

The deadliest blast Thursday occurred in Baghdad's southern Dora district, where a bomb exploded near an American foot patrol, U.S. and Iraqi officials said.

The U.S. military initially reported nine U.S. personnel were wounded in the attack. Later, the military said it could not confirm that number because the injured were still being evaluated and treated.

The attack occurred about 10:38 a.m. as the soldiers patrolled near an outdoor market, said Army Maj. David Shoupe.

Iraqi police said a suicide bomber was responsible, but Shoupe said the U.S. could not confirm that. He said four civilians died in the blast, but Iraqi police and hospital officials put the civilian toll at 12 killed and 25 wounded.

The officials spoke on condition of anonymity because they were not authorized to release the information.

Earlier Thursday, another suicide bomber killed seven U.S.-backed Sunni paramilitaries as they waited in a line to receive salaries at an Iraqi military base in the northern city of Kirkuk.

Police Maj. Salam Zankana said the victims in the Kirkuk attack were members of the local paramilitary Awakening Council — Sunnis who turned against the insurgents and help provide security. Eight others were wounded, he said.

Awakening Council members, also known as Sons of Iraq, have been frequently targeted by al-Qaida and other Sunni groups still fighting U.S. troops and the U.S.-backed Iraqi government.

Sami Ghayashi, 37, who was among the injured, said the local council members had been waiting three months to receive their salaries.

"While we were waiting at gate talking to one another a big explosion took place," he said from his hospital bed. "I saw several colleagues dead, among them my cousin. I have no idea how this suicide bomber got among us."

Also Thursday, a bomb exploded inside a police station in western Baghdad, killing three policemen and wounding 19 others, an Iraqi police official said. The bomb was hidden inside a trash can and carried into the station, he added.

The official also spoke on condition of anonymity because he was not authorized to release the information.

Despite a dramatic drop in violence in Iraq, attacks still occur, although with less frequency. Bursts of attacks tend to be followed by periods of calm, only to have the violence spring up again.

The attacks came a day after a car bomb exploded near a group of restaurants in a Shiite neighborhood of northwest Baghdad, leaving 41 people dead and more than 70 others injured.

That incident was the capital's first major car-bombing since May 6, when 15 people were killed at a produce market in south Baghdad.It was also the deadliest in the city since twin car blasts killed 51 people in another Shiite neighborhood, Sadr City, on April 29.

The failure to stop the bombings adds pressure on the Iraqi government to demonstrate that it can meet security challenges ahead of a June 30 deadline for the U.S. to remove all combat forces from Baghdad and other Iraqi cities.

A day after the Shula bombing, dozens were still being treated at an area hospital for shrapnel wounds and burns. The blast blew out the front of a building housing shops and restaurants.

Coffins draped with flags were carried through the streets near the bombing as funerals began for the dead.

U.S. troops are due to leave Iraqi cities under terms of the U.S.-Iraq security agreement that took effect Jan. 1. President Barack Obama plans to remove combat troops from the country by September 2010, with all U.S. forces out of Iraq by the end of 2011.

Under the agreement, Prime Minister Nouri al-Maliki could ask the U.S. to delay the pullout from the cities. However, the issue is politically sensitive in a country worn out by six years of war, and the government has insisted there will be no delay in the withdrawal schedule.