A car bomb exploded Tuesday as police exchanged fire with two attackers outside a police station south of Baghdad, wounding at least a dozen people, as gunmen kidnapped two dozen Iraqi workers.

The attack follows two days of violence in Iraq that left at least 151 dead, including 16 people killed Sunday in a military assault on what Iraqis claim was a mosque. Shiite politicians halted negotiations on a new government in response to the assault.

In Tuesday's attack, the men drove up to the police station in Iskandariyah and started firing machine guns at police, who fired back, hitting one of the assailants before the car blew up, police Lt. Col. Khalil Abdul-Ridha said.

Eleven police and a female bystander were wounded, he said. A series of mortar rounds then hit the police station, but nobody was harmed, he said.

Meanwhile, three groups of gunmen kidnapped at least 24 Iraqis working at a currency exchange and two electronics stores in Baghdad on Tuesday, the interior ministry said.

The abductions happened separately but within the same half-hour period, the ministry said.

Fifteen militants wearing military uniforms but arriving in civilian cars stormed the Moussa Bin Nasir Exchange Co. in the southwest Harthiyah neighborhood at about 1 p.m., kidnapping six people and stealing tens of thousands of dollars, police Lt. Col. Ali Rashid said.

At around the same time, seven gunmen in civilian clothes ran into a Daewoo International electronics store in the downtown Karradah district and snatched three employees, including the store manager, police Lt. Thaer Mahmoud said.

A half hour later, masked gunmen in military uniforms and helmets stormed a different branch of the same company in eastern Baghdad, abducting 15 employees, Lt. Col. Falah al-Mohmmedawi said. They also arrived in civilian cars.

The mass kidnappings came a day after gunmen abducted 16 employees of an Iraqi trading company in Baghdad's upscale western neighborhood of Mansour. Those kidnappers also wore uniforms and masks when they entered the headquarters of the Saeed Import and Export Co. Police said they went through papers and computer files before taking away their captives, al-Mohammadawi said.

Rafidh Salim Saleh, a worker at Saeed who avoided capture, said the company had been in Iraq more than 30 years and was involved with an electricity project in Youssifiyah, 12 miles south of Baghdad. He said a motive for the abductions was not known.

"The company has no political or terrorist ties or any activities that are anti-government," he said. "We don't even keep a gun."

In another attack on a locally owned security firm earlier this month, gunmen dressed as Interior Ministry commandos stormed into the al-Rawafid Security Co.'s east Baghdad headquarters and took away 50 people, many of them former military personnel from Saddam Hussein's regime. Those employees have not been heard from since the March 8 attack.

A curfew was imposed Tuesday on the northern city of Beiji, where the nation's largest oil refinery is located. Officials at a local military center said they were trying to prevent more violence after seven people were killed in the city last week.

In other violence, gunmen attacked a car carrying Iraqi contractors in Tikrit, 80 miles north of Baghdad, killing two and wounding one, police Capt. Hakim al-Azzawi said. The men provided construction and other services to U.S. troops, al-Azzawi said.

A roadside bomb targeting a police patrol exploded in the northern city of Kirkuk, wounding four policemen and two children walking to school, police said.

The firestorm of recrimination over the raid Sunday in northeast Baghdad will likely make it harder for Shiite politicians to keep a lid on their more angry followers as sectarian violence boils over. A unity government involving Shiites, Sunnis and Kurds is a benchmark for American hopes of starting to withdraw troops this summer.

There were numerous conflicting statements from Iraqis and the Americans about the raid. Iraqi police, Shiite militia officials and major politicians have all said the structure attacked was the al-Mustafa mosque. But the U.S. military disputed this, saying no mosques were entered and that the raid targeted a building used by "insurgents responsible for kidnapping and execution activities."

In a conference call with reporters early Tuesday, Lt. Gen. Peter Chiarelli, deputy commander in Iraq, and Maj. Gen. J.D. Thurman, commander of the 4th Infantry Division, which is in control of Baghdad, said 25 U.S. forces were in a backup role to 50 Iraqi Special Operations troops.

The mission, the generals said, was developed by the Iraqis on their intelligence that an Iraqi dental technician, kidnapped 12 hours earlier because he could not come up with $20,000, was being held in what they called an office complex.

"It's important to remember we had an Iraqi unit with us, an Iraqi unit of 50 folks and they told us point blank that this was not a mosque," Chiarelli said. "It's not Mustafa mosque. Mustafa mosque is located six blocks north on our maps of this location."

Associated Press reporters who visited the scene of the raid identified it as a neighborhood Shiite mosque complex. Television footage taken Monday showed crumbling walls and disarray in a compound used as a gathering place for prayer. It was filled with religious posters and strung with banners denouncing the attack.

In an earlier statement, the military said the building had been under U.S. observation for some time and gunmen opened fire as Iraqi special operations troops closed in. It said the troops then killed 16 insurgents and wounded three "during a house-to-house search," detained 18 men, found a significant weapons cache and freed the hostage.

"In our observation of the place and the activities that were going on, it's difficult for us to consider this a place of prayer," said Lt. Col. Barry Johnson, a U.S. military spokesman.

For their part, Iraqi police said gunmen fired on the joint U.S.-Iraqi patrol from a position in the neighborhood but not from the mosque.

Police and representatives of radical Shiite cleric Muqtada al-Sadr, who holds great sway among poor Shiites in eastern Baghdad, said all those killed were in the complex for evening prayers and none was a gunman. Police put the death toll at 17 — seven members of al-Sadr's militia, seven civilians and three Shiite political activists.

President Jalal Talabani, a Kurd, said an Iraqi-U.S. committee had been formed to investigate.

"I will personally supervise, and we will learn who was responsible. Those who are behind this attack must be brought to the justice and punished," Talabani said.

The Baghdad governor said he cut ties with U.S. forces and diplomats. And all 37 members of the Baghdad provincial council suspended cooperation with the United States in reconstruction projects planned for the remainder of the year, as well as political and security coordination, said council chairman Moeen al-Khadimi.

He said the local government would try to rely instead on the budget allocated to it by the Finance Ministry and on the money that comes from donor countries.

In other developments Tuesday, an Internet statement purportedly posted by the Mujahedeen Shura Council, a militant Sunni Muslim insurgent group, claimed responsibility for a suicide attack Monday near the gate of a U.S.-Iraq military base east of Tal Afar near the Syrian border.

The bomber, wearing an explosives vest, struck shortly after noon, killing at least 40 Iraqis and wounding 30 others, the Iraqi Defense Ministry said.

The council's statement said the bomber was a Saudi "martyrdom seeker."