At least 175 people were killed when three suicide bombers driving fuel tankers attacked a town, home to an ancient minority sect, in northern Iraq today in one of the worst single incidents in the four-year-old war.
Iraqi army Captain Mohammad al-Jaad said at least another 200 people were wounded in the bombings in separate Yazidi neighbourhoods in the town of Kahtaniya, west of Mosul.
A suicide bomber driving a fuel tanker killed 20 people and wounded 22 in a commercial and residential area of northern Iraq today, police said.
Meanwhile, US forces earlier launched a big offensive in Iraq with an overnight airborne assault targeting al Qaeda guerrillas today.
The Americans also raided Baghdad's Shi'ite slum of Sadr City targeting militants they said are linked to Iran. Relatives said a five-year-old girl was among four killed in the raid.
A suicide truck bomb killed 10 people and destroyed an important bridge linking Baghdad to the north, and 15 corpses identified as Sunni Arabs were found dumped by a highway.
The military said 16,000 US and Iraqi troops were involved in Operation Lightning Hammer against Sunni Islamist al Qaeda militants in the fertile crescent of the Diyala River which flows from the north into the Tigris near Baghdad.
US and Iraqi soldiers started the operation with a late-night air assault. Its focus was militants who fled an earlier crackdown in the provincial capital Baquba.
"Our main goal with Lightning Hammer is to eliminate the terrorist organisations...and show them that they truly have no safe haven - especially in Diyala," Major-General Benjamin Mixon, US commander in northern Iraq, said in a statement.
The operation was described as part of a larger countrywide Operation Phantom Strike, which US forces announced on Monday.
They have so far given few details of Phantom Strike. But US military offensives over recent months have been under way in the Tigris and Diyala valleys north of Baghdad and in the Euphrates valley south of the capital.