"The casualties are expected to rise as many victims are still trapped under the debris," Hassun said.

Abdul Rahim al-Shammari, mayor of Al-Baaj municipality, said about 70 houses were flattened by the bombings.

Scores of victims

Victims were taken to hospitals across northern Iraq as local clinics were unable to to cope with the number of dead and wounded.

"Scores of people are flocking to donate blood to save the wounded who are admitted in seven hospitals in Nineveh and Dohuk provinces," al-Shammari said.
A Kurdistan TV video grab of a man being
treated in a hospital in Dohuk [Reuters]

There has been no claim of responsibility for the attacks, but they bear similarities to attacks by al-Qaeda, which has been regrouping in northern Iraq.

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

Hoda Abdel Hamid, Al Jazeera's Iraq correspondent, that the areas where the attacks happened are considered "soft targets" because there is no large presence of Iraqi or US security forces.

"Over the past few months we have seen bolder attacks which are going further north ... so it is also a message from the attackers saying 'you might some success in one area but we can easily move to another area and there are many soft targets around the country'."

Yazidi sect

Yazidis are a primarily Kurdish sect that believes in God the creator and respect the Biblical and Koranic prophets, but the main focus of their worship is Malak Taus, the chief of the archangels.

In April, a Yazidi teenager who had recently converted to Islam was stoned to death after she reportedly fell in love with a Muslim and ran off with him.

A deadly car bombing hit a police patrol
 in Kirkuk on Tuesday [Reuters]
The incident appears to have sparked an increase in attacks on members of the sect.
 
The bodies of two Yazidi men who had been stoned to death were also found in the northern city of Kirkuk on Tuesday, police said.
 
In a second incident in the same city, one policeman was killed and eight others wounded - five of them civilians - when a police patrol was attacked by a car bomber.

Nuri al-Maliki, the Iraqi prime minister, has called for an investigation into what he called a "henious crime".

The US condemned Tuesday's bombings as "barbaric attacks on innocent civilians," and said it would help Iraqi forces "beat back these  vicious and heartless murderers", Dana Perino, White House spokeswomen, said.