U.S. troops killed five insurgents and destroyed a bomb-making factory Wednesday north of Baghdad, and dozens more were detained after fierce clashes in a Sunni-dominated province west of the capital.

Scattered violence killed at least nine people, while a claim by the U.S. military that insurgents used children in a weekend suicide attack raised concerns about new tactics being adopted by insurgents as a security crackdown aimed at stopping sectarian violence enters its sixth week.

Sunni Vice President Tariq al-Hashemi, meanwhile, renewed calls for talks to be opened with insurgents in an attempt to bring peace, but he excluded Al Qaeda in Iraq.

"I do believe that there is no way but to talk to everybody," he told the British Broadcasting Corp.

Apart from Al Qaeda, which he said was "not very much willing in fact to talk to anybody," all parties "should be invited, should be called to sit down around the table to discuss their fears, their reservations."

Maj. Gen. Michael Barbero, deputy director for regional operations on the Joint Staff, said Tuesday a vehicle used in the attack was waved through a U.S. military checkpoint because two children were visible in the back seat. He said this was the first reported use of children in a suicide car bombing in Baghdad.

"Children in the back seat lowered suspicion, (so) we let it move through, they parked the vehicle, the adults run out and detonate it with the children in the back," Barbero told reporters in Washington. "The brutality and ruthless nature of this enemy hasn't changed."

Other U.S. officials said later that three Iraqi bystanders were killed in the attack near a marketplace in the northern Baghdad neighborhood of Azamiyah, in addition to the two children, and seven people were injured. The officials had no other details, including the estimated ages of the children.

Lt. Col. Christopher Garver, a U.S. military spokesman in Baghdad, confirmed Barbero's account but said he couldn't provide more details.

An Iraqi police officer, speaking on condition of anonymity because of security concern, said witnesses had reported seeing two children inside the car before it exploded. He said eight civilians were killed and 28 others wounded in the attack in the predominantly Shiite northern neighborhood of Shaab.

The police officer also said three other cases had been registered since last year in which women and children were used in parked car bombings, although they reportedly got out of the autos before the explosions in those cases.

The U.S. military has warned that insurgents are proving adaptable and finding new ways to bypass stepped up security measures and kill as many people as possible. A series of bombings using toxic chlorine since Jan. 28 also raised concerns.

U.S. forces killed five suspected insurgents, detained three others and used an airstrike to destroy a bomb-making factory that contained large-caliber ammunition and several 50-gallon barrels of explosive material near Taji, an air base 12 miles north of Baghdad, the military said. No American troops or civilians were wounded in the operation, it added.

A Sadrist lawmaker, Bahaa al-Araji, also said U.S. troops raided his office Wednesday, seizing the memory card from his computer along with a gun and a rifle. The U.S. military had no immediate comment.

Al-Araji, one of 30 members of parliament loyal to radical Shiite cleric Muqtada al-Sadr, called the raid a violation of Iraq's sovereignty. "It is a message of provocation sent to the al-Sadr movement," he told The Associated Press in a telephone interview. "We will not be drawn into this confrontation."

"We are with the security plan, but we think that the searches should be done by Iraqi forces," he added.

Al-Sadr, who the military claims has gone to Iran, was said to have ordered his Mahdi Army militia to put away its weapons and not confront U.S. and Iraqi troops during a U.S.-Iraqi security sweep aimed at stopping the sectarian violence in Baghdad.

The success in reining in al-Sadr's Mahdi Army militia, which fought fiercely against U.S. forces in 2004, is widely credited with the drop in execution-style killings, random shootings and rocket attacks during the five-week-old operation, but there have been indications that some factions are unhappy with being sidelined.

West of Baghdad, U.S.-Iraqi troops backed by American warplanes battled al-Qaida-linked insurgents for more than five hours Tuesday in clashes in Amiriyah, near Fallujah, that left eight militants dead and five Iraqi policemen wounded, the military said.

Police also detained 45 insurgents, confiscated propaganda material and discovered several weapons caches in house-to-house searches Tuesday in the Anbar provincial capital of Ramadi, the military said separately. A roadside bomb planted during the 10-hour operation killed one civilian and wounded five, it said.

In other violence Wednesday, according to police:

— A mortar attack struck a residential area in Madain, about 14 miles southeast of Baghdad, killing three civilians and wounding 10.

— Roadside bombs targeting police patrols in eastern Baghdad, killing three people and wounded two others.

— One civilian was killed and seven were wounded when Iraqi police detonated a truck full of explosives after spotting it parked about near the Finance Ministry building in northern Baghdad.

— The bodies of two policemen, handcuffed and showing signs of torture, were found in Diwaniyah, the site of recent clashes 80 miles south of Baghdad.