A spate of bomb attacks against police in the disputed northern oil-rich city of Kirkuk on Thursday killed at least 27 people, the worst violence to hit Iraq in nearly two months.

File picture shows Iraqi soldiers patrolling in the oil-rich northern city of Kirkuk.

A further 89 people were wounded in the three attacks, with months to go before US forces, who participate in confidence-building tripartite patrols and checkpoints with central government forces and Kurdish security officers in Kirkuk and across north Iraq, must withdraw from the country.

Three explosions -- two car bombs and a magnetic "sticky bomb" attached to a car -- occurred around one hour apart in the oil-rich ethnically-mixed city, security officials said.

The first of the blasts took place at 9:20 am (0620 GMT) when the "sticky bomb" exploded in the parking lot of the city\'s police headquarters, Major Salam Zangan said.

When police and emergency responders arrived at the scene shortly afterwards, a car bomb detonated.

"I ran out from the headquarters after I heard the first bomb -- I went with my colleague to check the parking lot but as we arrived, a huge bomb went off," said Sherzad Kamil, a policeman who suffered wounds to his abdomen and face.

"I fell on the ground and saw several of my colleagues killed and wounded," he said, speaking from Kirkuk general hospital, adding that he saw colleagues whose bodies caught fire as a result of the second blast.

Kirkuk provincial health director Sadiq Omar Rasul said 27 people were killed and 89 others wounded as a result of the three explosions, with the majority of the casualties being policemen.

A senior security official, speaking on condition of anonymity, confirmed the toll. An interior ministry official in Baghdad, meanwhile, said 29 people had died and 80 were wounded in the three blasts.

The first two blasts caused massive damage to nearby police and civilian vehicles, and several police cars with loudspeakers affixed to them could be heard appealing to Kirkuk residents to make their way to the city\'s hospital to donate much-needed blood for victims, an AFP journalist said.

At around 10:30 am, another car bomb exploded near the convoy of a senior police official in Kirkuk, Colonel Aras Mohammed.

He and 13 of his bodyguards were wounded in the blast, which also caused serious damage to several nearby cars and buildings, a Kirkuk security official said, on condition of anonymity.

Kirkuk lies at the centre of a tract of disputed territory that is claimed by both Iraq\'s central government in Baghdad and Kurdish regional authorities in Arbil.

US officials have persistently said that the unresolved row is one of the biggest threats to Iraq\'s future stability.

The attacks in Kirkuk come just a day after the Iraqi army announced the arrest of the alleged military leader of Al-Qaeda\'s offshoot in Iraq along with three of his acolytes in a raid.

Thursday\'s death toll was the highest in Iraq since March 29, when a band of Al-Qaeda gunmen and suicide bombers managed to storm a provincial council building in the central city of Tikrit killing 58 people.

In separate bomb attacks in Baghdad and the restive central city of Baquba on Thursday, meanwhile, a woman and an imam were killed and 10 others wounded, security officials said.

Violence is down dramatically in Iraq from its peak, but attacks remain common. A total of 211 Iraqis were killed in violence in April, according to official figures.