Nine security guards were killed in northern Iraq when a roadside bomb they were trying to defuse blew up.

Four other security officers were injured in the explosion, which happened about 12km northwest of the city of Kirkuk at about 11.30am Irish time.

The local police chief said that the security guards were protecting oil facilities for the Northern Oil Company. 

They had managed to deactivate a device at the roadside before a second device exploded.

In Baghdad there was a series of explosions, including a bomb that struck an oil tanker.

Another bomb detonated on the road to the airport, injuring seven Iraqis.