Rescuers dug through the muddy wreckage of collapsed clay houses in northwest Iraq on Wednesday, uncovering at least 250 bodies from suicide truck bombings the U.S. military blamed on Al Qaeda, making it the deadliest attack since the war began.
The victims of the war's second-deadliest attack were members of the Yazidis, a small Kurdish sect that has been the target of Muslim extremists who label it blasphemous.
Four suicide truck bombers struck nearly simultaneously on Tuesday, causing buildings to crumble and trapping entire families underneath the wreckage.
Zayan Othman, the health minister of the nearby autonomous Kurdish region, said the casualty toll had risen to at least 250 killed and 350 wounded as bodies were pulled from the rubble. That surpassed the previous deadliest attack of the war when 215 people were killed by mortar fire and five car bombs in Baghdad's Shiite Muslim enclave of Sadr City on Nov. 23.
U.S. officials believe extremists are attempting to regroup across northern Iraq after being driven from strongholds in and around Baghdad, and commanders have warned they expected Sunni insurgents to step up attacks in a bid to upstage the report.
"This is an act of ethnic cleansing, if you will, almost genocide, when you consider the fact of the target they attacked, and the fact that these Yazidis are really out in a very remote part of Ninevah province," Army Maj. Gen. Benjamin Mixon, the commander of U.S. forces in northern Iraq, said after the attacks.
Mixon said last month that he proposed reducing American troop levels in Ninevah and predicted the province would shift to Iraqi government control as early as this month. It was unclear whether that projection would hold after Tuesday's staggering death tolls.
Police said separately that five people were killed in an ambush Wednesday on a minibus carrying civilians near Khalis, about 50 miles north of Baghdad, where suspected Al Qaeda militants had set up a fake checkpoint. A 5-year-old was among the dead.
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In the main northern city of Mosul, a bomb in a parked car killed a civilian and wounded ten others, police and army officers said. A police patrol appeared to have been the target.
South of Baghdad, meanwhile, a suicide car bomber killed two people and wounded seven, Iraqi police said.
The carnage dealt a serious blow to U.S. efforts to pacify the country with just weeks before top U.S. commander Gen. David Petraeus and U.S. Ambassador Ryan Crocker are to deliver a pivotal report to Congress amid a fierce debate over whether to begin withdrawing U.S. troops from Iraq.
Dakhil Qassim, the mayor of the nearby town of Sinjar, said the four trucks approached the town of Qahataniya, 120 kilometers (75 miles) west of Mosul, Iraq's third-largest city, from dirt roads and all exploded within minutes of each other. He said the casualty toll was expected to rise.
"We are still digging with our hands and shovels because we can't use cranes because many of the houses were built of clay," Qassim said. "We are expecting to reach the final death toll tomorrow or day after tomorrow as we are getting only pieces of bodies."
"The car bombs that were used all had the consistent profile of al-Qaida in Iraq violence," U.S. military spokesman Brig. Gen. Kevin Bergner told reporters in Baghdad's heavily fortified Green Zone.
Iraqi Prime Minister Nouri al-Maliki issued a statement blaming the bombings on "terrorism powers who seek to fuel sectarian strife and damage our people's national unity."
The Yazidis are a primarily Kurdish religious sect with ancient roots that worships an angel figure considered to be the devil by some Muslims and Christians. Yazidis, who don't believe in hell or evil, deny that.
The Islamic State in Iraq, an Al Qaeda front group, distributed leaflets a week ago warning residents near the scene of Tuesday's bombings that an attack was imminent because Yazidis are "anti-Islamic."
The sect has been under fire since some members stoned a Yazidi teenager to death in April. She had converted to Islam and fled her family with a Muslim boyfriend, and police said 18-year-old Duaa Khalil Aswad was killed by relatives who disapproved of the match.
A grainy video showing gruesome scenes of the woman's killing was later posted on Iraqi Web sites. Its authenticity could not be independently verified, but recent attacks on Yazidis have been blamed on Al Qaeda-linked Sunni insurgents seeking revenge.
A curfew was in place Wednesday across towns west of Mosul, and U.S. and Iraqi forces were conducting house-to-house searches in response to the bombings, according to Iraqi police and Army officers who spoke on condition of anonymity out of security concerns. Twenty suspects were arrested, they said.
Meanwhile, U.S. troops killed 11 suspected terrorists and detained four others in operations against Al Qaeda in central and northern Iraq, the military said in a statement.
Ten thousand U.S. troops and 6,000 Iraqi soldiers are involved in air and ground assaults across Diyala and Salahuddin provinces, both north of Baghdad, in a nationwide offensive against Sunni insurgents with links to Al Qaeda and Shiite militiamen.
More than 300 artillery rounds, rockets and bombs were dropped in the Diyala River valley late Monday and early Tuesday, and three suspected Al Qaeda gunmen were killed and eight were taken prisoner, the military said. U.S. troops also discovered several roadside bombs rigged to explode.
Complete coverage is available in FOXNews.com's Iraq Center.