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.

AFP