At least 48 people have been killed after an explosion ripped through a secondary school in northeast Nigeria, as student gathered for morning assembly before classes began.

A teacher at the school, a medic and a rescue worker said on Monday that blast happened at Government Comprehensive Senior Science Secondary School in Potiskum, Yobe State.

The rescue worker told AFP news agency that 13 bodies had been taken to hospital with more than 30 others left “with various degrees of injuries”. There was no official death toll.

The student had gathered for assembly when something exploded in their midst with a thunderous sound at exactly 7:50am local time (0650 GMT),”added a teacher, who asked not to be identified.

A medic at the Potiskum General Hospital,where the victims were taken,said scores of student had been taken admitted.

“We are still receiving casualties from the school which is a stone throw from here,” the medic said

“Our priority now is to save the injured, so we have not started a headcount of the victims.”

Attacks on school by the armed group Boko Haram are common in northern Nigeria,where the fighters have control over large areas.

The group, whose name means Western Education is sinful” in the local Hausa language, is indeed the biggest threat to security in Nigeria right now , which is Africa biggest economy and leading oil producer.

The latest violence came days after a suicide bomber killed at least seven people outside a commercial bank in the northeast town of Azare on Friday.

The suicide bomber is said to have dressed as one of the students in school uniform and joined in the assembly before detonating the explosives. Security agencies has since cordoned off the place while the rescue workers are trying their best to save some of the victim who sustained various degrees of injuries