An explosion and gunfire shook an area around an Islamic school in northern Nigeria on Sunday, leaving two suspected attackers dead and others wounded, emergency officials said.

Details of the blast in the northern city of Zaria were sketchy, with initial reports saying that the blast occurred inside the school but a government spokesman later saying that it went off near it.

"It's close to a boarding school called Albani," National Emergency Management Agency spokesman Yushau Shuaib told AFP.

"Two suspects were killed. The innocent victims that were injured were taken to hospital."

Two of the presumed attackers were killed when they exchanged gunfire with security forces after the explosion, he said.

Another relief official said there had also been an exchange of fire between security forces and gunmen Saturday night.