The US military said on Wednesday al Qaeda was the “prime suspect” in the suicide bomb attacks on a minority sect that killed 200 people in northwestern Iraq.

Rescue workers searched for bodies in the rubble of dozens of buildings destroyed in up to five simultaneous car bomb attacks overnight.

The attackers, driving fuel tankers, struck densely populated residential areas west of the city of Mosul that are home to members of the Yazidi sect, whose followers are considered infidels by Sunni Islamist militant groups.

The US military said it was too early to say who was responsible, but the scale and apparently coordinated nature of the bombings were hallmarks of Sunni Islamist al Qaeda. The United States condemned the attack as barbaric.

“We're looking at al Qaeda as the prime suspect,” said US military spokesman Lieutenant-Colonel Christopher Garver.

The mayor of the district of Sinjar, Dakheel Qassim Hasoun, said 200 people had been killed. The remoteness of the area made it difficult to get details of the attacks or the number of casualties.

If confirmed, the death toll would be the highest in any one attack since November, when six car bombs in different parts of Baghdad's Shi'ite Sadr City district killed 200 people and wounded 250. Car bombs killed 191 around Baghdad on one day in April.

The Kurdistan Regional Government (KRG) condemned “the cowardly and barbaric attack against innocent civilians of this tolerant religious minority”.

“The Kurdistan Regional Government remains steadfast in its resolve to help the Iraqi government and security forces to bring to justice the murderers responsible for planning these cowardly acts,” it added in a statement.

Condemnation
The US military has launched a major new offensive in Iraq in a bid to thwart such attacks by al Qaeda and Shi’ite militias ahead of a progress report on the US military strategy in Iraq that is due to be presented to the US Congress in September.

“This indiscriminate and heartless violence only strengthens our resolve to continue our mission against the terrorists who are plaguing the people of Iraq,” US ambassador Ryan Crocker and military commander General David Petraeus, who will both deliver the progress report, said in a joint statement.

In the aftermath of the blast, authorities imposed a total curfew in the Sinjar area, which is close to the Syrian border.

Mayor Hasoun said only people and vehicles involved in rescue efforts would be allowed to move through the area.

He said it would be impossible to establish a final death toll any time soon because many bodies were still buried in the rubble of up to 30 houses destroyed in the blasts.

US assistance
Lieutenant-Colonel Mike Donnelly, US military spokesman for northern Iraq, said US forces were assisting Iraqi emergency agencies as they sifted through the rubble and were providing logistical, security and medical support.

Authorities said the death toll was so high because most of the destroyed houses, packed in three Yazidi residential compounds, were made of mud that shattered with the force of the blasts. “It is going to be difficult to get a full death toll because of the nature of the buildings,” Garver said.

The US military said five vehicle-borne bombs had been detonated in Yazidi residential compounds in the villages of Kahtaniya and al-Jazeera. Jaad said the village of Tal Uzair was also hit.

Yazidis are members of a pre-Islamic Kurdish sect who live in northern Iraq and Syria. Sunni militants have kidnapped and killed many in recent months.

Yazidis in Iraq say they have often faced persecution because the chief angel they venerate as a manifestation of God is often identified as the fallen angel Satan.