Baghdad, Iraq ? U.S. forces launched airstrikes killing 40 purported insurgents in western Iraq on Saturday, while insurgents carried out car bombings and other attacks in and around the capital that left at least 31 dead.

An attack by a former member of the Iraqi police Wolf Brigade was the most audacious assault in a day that saw violence against Iraqi and U.S. security forces, the Slovakian Embassy and civilians.

Dressed in a police uniform with explosives strapped to his body, a former member of the elite Iraqi police brigade walked into his old unit’s roll call and detonated a suicide bomb that killed three of his former colleagues, Iraqi Interior Minister Bayan Jabr said.

Three men suspected of assisting the suicide bomber were detained in Latifiyah, south of the capital, soon after the attack, Jabr said.

The motivation for the attack was unclear Saturday. The Wolf Brigade has a mixed reputation in Iraq. The Iraqi government has launched a strong public-relations campaign on behalf of the force, including commercials extolling the elite brigade’s bravery and know-how.

But some in the country’s minority Sunni community have accused the brigade of kidnapping and killing Sunni leaders. The force is often derisively referred to as the “thieves’ brigade” in some Sunni circles.

The latest spurt of violence began Friday evening when a car bomb exploded outside a health clinic in the busy Shula neighborhood. At least 10 people were killed and 27 wounded, an Interior Ministry official said. Eight people believed to be involved in the car bombing have been detained by Iraqi authorities for questioning, Jabr said.

Gunmen also sprayed gunfire at a mini-bus traveling through Diyara, 30 miles south of Baghdad. The bus was carrying Iraqi workers at U.S. military bases, and at least 11 of the workers were killed, an Interior Ministry official said.

In western Baghdad, gunmen in a speeding car attacked an Interior Ministry commando convoy, killing three officers, police told The Associated Press.

Separately, two Oil Ministry employees were shot to death and another man was wounded in southern Baghdad. In another attack, a bomb exploded in a cemetery in the Shiite holy city of Najaf, killing two Iraqis who were visiting the graves of relatives, according to AP.

On Saturday afternoon, a suicide car bomber ran his explosives-laden vehicle into the Slovakian Embassy, wounding four. The bombing left a 7-foot-wide crater in the front yard of the embassy and broke windows blocks away.

“We were inside the shop and heard a huge boom,” said Jafaar Abbas, 31, a shopowner across the street from the embassy as he swept up damaged goods that were knocked off shelves by the blast. “We went out to see what it was, and everything was burning.”

Little was known late Saturday about the U.S. airstrikes in Karabilah, which is near Qaim, a volatile city where U.S. forces carried out a major operation last month. The attacks come during a particularly violent period for U.S. forces charged with securing western Anbar province.

The U.S. military reported Saturday that two Marines were killed a day earlier when the vehicle they were traveling in was struck by a roadside bomb in Saqwaliyah, west of Fallujah. On Thursday, five Marines were killed when a roadside bomb struck their vehicle in Haqliniyah.

Despite the reports of violence throughout the country, Jabr, the interior minister, said during his news conference that the country’s security is on the mend. He predicted that Iraqi forces would have the situation under control within six months.