A homicide minibus bomber killed 12 people Monday, including three children, in an attack targeting members of predominantly Sunni tribal groups who turned against Al Qaeda in Iraq — days after Usama bin Laden warned Sunnis not to join the U.S.-backed fighters.

The rapidly expanding groups, known as Awakening Councils, have been credited with helping slash the level of violence across the country by 60 percent since June. But their new allegiance with the U.S. military and Iraqi government forces has made them targets.

Usama bin Laden, in an audiotape that emerged on Saturday, warned Iraq's Sunni Arabs against joining the Awakening Councils or participating in any unity government.

Council leaders hit back.

"We consider our fighting against Al Qaeda to be a popular revolution against the devil," said Sheik Mohammed Saleh al-Dohan, head of Awakening Council operations in southern Ramadi, the main town of Anbar province where the Awakening movement was born. "We helped all Iraqis ... and especially those in Ramadi to get rid of kidnappings, beheadings and sectarian divisions."

Al-Dohan blamed Al Qaeda for bringing destruction to Iraq.

"They made enemies between Sunnis, Shiites and Christians who lived in peace for centuries," he said. "We are fighting the renegades (Al Qaeda fighters) who used Islam's interpretation as a cover for their atrocities.

"Bin Laden is losing ground in Ramadi and most of the Iraqi territories which were under the thumb of his fighters. He and his organization are the traitors who betrayed the Muslim nation and brought shame to Islam in all the world," he said, adding that the Awakening Councils would continue to hunt down Al Qaeda fighters "everywhere until they are eliminated."

In the northern city of Tikrit, the local Salahuddin Awakening Council distributed a statement saying the main reason for founding the movement was "the crimes of followers of Usama bin Laden in Iraq."

The "Awakening Council's fighters are protecting people from criminals and from those who violate the indignity of the people," the statement said, and demanded an apology "for those who have been harmed by the brutal acts of Al Qaeda members."

The Awakening Councils — dubbed Concerned Local Citizens by the U.S. military — began in Anbar province, once a hotbed of Al Qaeda in Iraq activity, and has since grown into a mass movement that includes more than 70,000 mostly Sunni fighters who are paid a monthly salary of US$300 (about euro200) by the U.S. to protect their neighborhoods.

Awakening members were the target of several attacks on Monday.

In the most serious, a homicide bomber drove a minibus rigged with explosives into an Awakening Council checkpoint in Mishada, part of the city of Tarmiyah, 50 kilometers (30 miles) north of Baghdad, police and a member of the council said.

The explosion killed 12 people — three children on their way to school and nine council members, said Adil al-Mishhadani, a member of the Awakening Council. Another three people were missing, believed blown up by the blast, he said.

In the capital, a mortar round believed to have been targeting an Awakening Council headquarters wounded three civilians when it landed on a nearby house in Baghdad's western neighborhood of Amariyah Monday, a Baghdad police officer said on condition of anonymity because he was not authorized to release information to the media.

To the south in Wasit province, gunmen shot and wounded an Awakening Council member in the village of al-Hafriyah, 160 kilometers (100 miles) southeast of Baghdad, police said.

In the town of Khalis, 80 kilometers (50 miles) north of Baghdad, gunmen traded fire with police and Awakening Council members, leaving one council member and one policeman dead and wounding three policemen, a police officer said.

Separately, six mortar rounds landed near an Iraqi Army checkpoint near the town, wounding two soldiers, the officer said.

In other violence, a female homicide bomber detonated herself near a police patrol, wounding five policemen and four civilians in the town of Baqouba, 60 kilometers (35 miles) northeast of Baghdad, said police Brig. Khudeir al-Tamimi.

To the south in Suwayrah, 40 kilometers (25 miles) south of Baghdad, a roadside bomb exploded outside a car showroom, seriously injuring two civilians, police said.

Earlier, a roadside bomb targeting a border patrol near the Iranian border killed two Iraqi border guards and injured another four, police said.

The attack occurred shortly after dawn in the frontier town of Mandali, about 50 kilometers (30 miles) from the Iranian border in Diyala province northeast of Baghdad, a police officer said on condition of anonymity as he was not authorized to release information to the media.

Mohammed Mulla Karim, mayor of a nearby town, said one border guard was killed in the explosion and four were wounded. The differing death tolls could not immediately be reconciled.