Three policemen and five militants were killed on Monday by a car suicide bomb at a checkpoint on the outskirts of Damaturu, capital of Yobe state in northern Nigeria, a police spokesman said.

The checkpoint is on a highway that connects the city with Borno state capital Maiduguri.

The road and villages along it are frequently hit by bombs or raids by suspected members of Islamist jihadist group Boko Haram.

“We were stopped by the army at a checkpoint. There was an SUV (sports utility vehicle) about five cars away from us. I believe two people were in that car … One came out and suddenly there was a loud sound and smoke filled the air,” Ahmed Mohammed, who was driving towards Damaturu from Maiduguri, said.

Police spokesman Toyin Gbadegasin said that three of the people killed were policemen and the remainder were militants. He said police had intercepted two cars loaded with explosives and then the SUV blew up.

On Friday, at least 50 people were killed in Damaturu by two female suicide bombers as worshippers gathered to mark the Muslim holiday Eid al-Fitr.

On Thursday, another 50 people were killed by bombs in another northeastern city, Gombe.