Explosives were concealed in a vehicle and detonated, causing a large fireball, at a market in Maiduguri, the capital of Borno state with a population of about 1.2 million people. Nearby cars and taxis were destroyed in the explosion, allegedly caused by a suicide bomber.
"A van loaded with charcoal and IED (improvised explosive device) exploded at Monday Market in Maiduguri this morning. The location has been cordoned," the local defense headquarters reported.
"I heard a very loud explosion right from my house and rushed to the place. When I got there I saw many people lying after they were hit by explosives," a witness, Babagana Hausari, told the BBC.
A medical worker said at least 55 people were injured in the incident.
Although no group has taken responsibility for the explosion, it came after the Nigerian army announced Monday it had raided a Boko Haram cell connected to the April abduction of 200 girls from their school. It added cell leader Babuji Ya'ari was arrested.