A suicide truck bomb has exploded in the northern Iraqi city of Baiji, killing at least 22 people and wounding 80, police and local hospital officials said.

The bomber detonated his explosives when police and members of a volunteer security force prevented him from entering the gate of a compound housing employees of state-run North Oil Company.

A Reuters photographer at the scene said the blast set six vehicles ablaze and left a large crater in the road.

Four apartment blocks in the residential complex were severely damaged.

Among those killed were members of the volunteer force, guards of the oil company and civilians, including at least three children, the police officer said.

Iraq's interior minister ordered the dismissal of Saad Nufous, Baiji's police chief, shortly after the blast.

Major-General Abdul-Karim Khalaf, an interior ministry spokesman, said: "There was a decision by the interior ministry to fire the Baiji police chief."

In a separate attack, a suicide bomber struck the funeral of a father and son working as armed volunteers with US forces north of Baghdad, killing four people and wounding 21, police said.

PHOTO CAPTION

An Iraqi soldier rushes a wounded child into a hospital in the restive city of Baquba