BAGHDAD - Four suicide bombers struck nearly simultaneously at communities of a small Kurdish sect in northwestern Iraq late Tuesday, killing at least 175 people and wounding 200 more, Iraqi military and local officials said.
The death toll was the highest in a concerted attack since Nov. 23, when 215 people were killed by mortar fire and five car bombs in Baghdad's Shiite Muslim enclave of Sadr City.
And it was most vicious attack yet against the Yazidis, an ancient religious community whose members are considered infidels by some Muslims in the region.
The bombings came as extremists staged other bold attacks: levelling a key bridge outside Baghdad and abducting five officials from an Oil Ministry compound in the capital in a raid using gunmen dressed as security officers.
Nine U.S. soldiers also were reported killed, including five in a helicopter crash.
The U.S. military, meanwhile, sought to press its gains against guerrillas.
Some 16,000 U.S. and Iraqi soldiers began a sweep through the Diyala River valley north of Baghdad in pursuit of Sunni insurgents and Shiite militia fighters driven out of strongholds in recent weeks.
U.S. officials believe extremists are attempting to regroup across northern Iraq after being driven from strongholds in and around Baghdad.
Such a retrenching could increase pressure on small communities such as the Yazidis, a primarily Kurdish group 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 websites. Its authenticity could not be independently verified, but recent attacks on Yazidis have been blamed on al Qaeda-linked Sunni insurgents seeking revenge.
The suicide bombings came just after sundown near Qahataniya, 120 kilometres west of Mosul, Iraq's third-largest city, said Abdul-Rahman al-Shimiri, the top government official in the area, and Iraq army Capt. Mohammed Ahmed.
At least one of the trucks was an explosives-laden fuel tanker, police said. Shops were set ablaze and apartment buildings were reported crumbled by the powerful explosions.
"My friend and I were thrown high in the air. I still don't know what happened to him,'' said Khadir Shamu, a 30-year-old Yazidi who was injured in Tal Azir, scene of two blasts.
Witnesses said U.S. helicopters swooped in to evacuate wounded to hospitals in Dahuk, a Kurdish city near the Turkish border about 100 kilometres north of Qahataniya. Civilian cars and ambulances also rushed injured to hospitals in Dahuk, police said.
"I gave blood. I saw many maimed people with no legs or hands,'' said Ghassan Salim, a 40-year-old Yazidi teacher who went to a hospital to donate blood. "Many of the wounded were left in the hospital garage or in the streets because the hospital is small.''
The U.S. administration denounced the bombings as "barbaric attacks on innocent civilians.'' White House deputy press secretary Dana Perino expressed sympathy to the families of those killed or wounded.
There was no claim of responsibility, but the attack bore the hallmark of al-Qaida in Iraq, which has been regrouping in the north after being driven from safe havens in Anbar and Diyala provinces.
"This is a terrorist act and the people targeted are poor Yazidis who have nothing to do with the armed conflict,'' said Dhakil Qassim, mayor in the town of Sinjar near the attacks who blamed al-Qaida in Iraq.
Two weeks after the Yazidi woman was stoned to death, gunmen killed 23 Yazidis execution-style after stopping their bus and separating out followers of other faiths in what was believed to have been retaliation for the woman's death.
The bodies of two Yazidi men who had been stoned to death turned up in the morgue in the northern city of Kirkuk on Tuesday, six days after they had been kidnapped while en route to Baghdad to sell olives, police said.
"We are still paying the price of a foolish, wrong act conducted by small number of Yazidis who stoned the woman,'' said 44-year-old Sami Benda, a relative of one of the slain men.
The centre of the Yazidi faith is around Mosul, but smaller communities exist in Turkey, Syria and other places.
Baghdad was spared major violence in another sign that a six-month-old security crackdown in the capital is disrupting extremists' firepower. But the brazen daylight raid on the Oil Ministry complex showed that armed gangs can still embarrass authorities.
Dozens of gunmen wearing security force uniforms stormed the compound and abducted a deputy oil minister and four other officials who were spirited away in a convoy of military-style vehicles.
The kidnappings -- similar to a commando-like raid on Iraq's Finance Ministry in May -- included Abdel-Jabar al-Wagaa, a senior assistant to Oil Minister Hussain al-Shahristani, said Assem Jihad, the oil ministry spokesman.
Al-Wagaa and four other officials with the State Oil Marketing Organization were taken away by more than 50 gunmen in military-style vehicles, said an Interior Minister official.
Five bodyguards were wounded in the raid, the official said.
