There has been sporadic shooting in Maiduguri, the capital of Borno State.
Residents said the affected part of the city was the Jidari Polo area and the attack occurred at about 7 p.m. local time on Wednesday.
Eyewitnesses say suspected members of Boko Haram may have infiltrated the city.
Meanwhile, the army says the attempt by few suspected Boko Haram members to attack Jiddari Polo has been neutralised.
Army spokesman, Brigadier General Sani Usman assures residents that the situation is cool and calm.
He adds that Maiduguri is under the control of the military and requested the public not to panic.