A further 89 people were wounded in the three attacks, with just months to go before US forces must withdraw from the country.
And in separate bombings in Baghdad and the central city of Baquba, a woman and an imam were killed and 10 others wounded, security officials said.
Two car bombs and a magnetic "sticky bomb" attached to a car exploded in ethnically mixed Kirkuk, security officials said.
The first blast 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 was wounded in the 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 in the second blast.
Kirkuk provincial health director Sadiq Omar Rasul said 27 people were killed and 89 others wounded in the three explosions, with the majority of the casualties being policemen.
A senior security official confirmed the toll, adding that all but one of the dead were policemen, while an interior ministry official in Baghdad said 29 people had died and 80 were wounded.
Five of the wounded remain in critical condition, according to a doctor at Kirkuk general hospital.
The first two explosions caused massive damage to nearby police and civilian vehicles. Afterwards, several police cars with loudspeakers affixed to them could be heard appealing to people 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 detonated near the convoy of a senior police official in Kirkuk, Colonel Aras Mohammed.
Mohammed was wounded in the blast, which seriously damaged several nearby cars and buildings, a Kirkuk security official said.
Kirkuk lies at the centre of a tract of disputed territory that is claimed by both Iraq`s central government and by Kurdish regional authorities.
US officials have persistently said that the unresolved row is one of the biggest threats to Iraq`s future stability.
Currently, US forces participate in confidence-building tripartite patrols and checkpoints with central government forces and Kurdish security officers in Kirkuk and across northern Iraq.
But the withdrawal of some 45,000 US troops still in Iraq must be completed by the end of the year. As part of those efforts, American forces handed over Contingency Operating Location McHenry in the town of Hawija, west of Kirkuk, to their local counterparts on Sunday.
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 stormed a provincial council building in the central city of Tikrit, killing 58 people.
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. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011
