Sources at the University of Maiduguri (UniMaid) told the BBC they heard an explosion and gunshots on campus at about 21.30 local time (20:30 GMT).

Fleeing students believe the attack was carried out by Boko Haram militants and the hashtag #UniMaid was trending overnight.

Security forces are said to be on high alert and reinforcements have been sent to the university, which is in the capital of Borno state, reports BBC Nigeria correspondent Mayeni Jones.

There have been no confirmed reports of casualties so far.

“It was a Boko Haram attack which has been repelled effectively by our soldiers,” a top army official in Maiduguri told Nigeria’s Premium Times newspaper.

“We have all been lying down on the floor since the shooting commenced; it lasted for about one an hour,” one student told the newspaper.

A local journalist told the BBC Newsday programme that people are on edge in the city, which has been prone to attacks from Boko Haram militants.

The militants have waged a 10-year-long insurgency in the region, which has displaced hundreds of thousands of people.