The militant group, Boko Haram, is being blamed for an attack on a school in northeastern Nigeria in which 46 students were killed.
The bomb ripped through the school in Potiskum as students gathered for assembly before classes.
"There was an explosion detonated by a suicide bomber. We have 48 dead and 79 injured," said national police spokesman Emmanuel Ojukwu.
Mr Ojukwu said most of the dead were students and teachers.
Mr Ojukwu also confirmed media reports that the bomber was disguised in a school uniform, which allowed him to pass unnoticed at the school.
No one has yet claimed responsibility for the attack in Yobe State.
However, the territory has been hit by an insurgency by Islamist Boko Haram rebels.
At least 29 people were killed in another bombing in the town on 3 November.
