At least one police officer was killed in Kano state on Wednesday, police officials said, when gunmen ambushed a checkpoint in Madobi, near the Sani Abacha Youth Center, reports said.

The assailants, suspected to be members of Boko Haram, arrived in a Golf VW and three motorbikes and launched the surprise attack at the checkpoint.

Security forces made a quick comeback after the initial shock of the attack and pursued the suspected insurgents who left behind their transport and took off on foot.

Explosives were found already planted at the scene ahead of a planned attack. State Commissioner of Police in the state, Alhaji K Idris, said a special bomb unit was called in to defuse the device. The IEDs were disposed off in controlled detonations, but sounds of explosions caused further panic among residents in the restive northern city.

Boko Haram has claimed responsibility for a spate of bombings targeting churches and security agents in the north. It has promised more attacks in the north, a source said, and is plotting to make June its bloodiest campaign yet.

On Tuesday, the acting IGP, Mohammed Abubakar announced a 24-hour strategic police patrol in Kaduna, Kano, Plateau and other key northern states. The new strategy will also include intennsified security at places of worship on Sundays, when the sect is often known to strike.

The search for the attackers is still underway in Kano.