Disposal experts said that the fuse on the bomb had been lit, but went out before it could cause an explosion.
The homemade device could not be set off using remote control.
It contained about one kilogramme of explosives and was about 22 cm long and cylindrical in shape.
Early police investigations have suggested the device was supposed to blow up a cash machine outside the school.
This is coming as the team of Police Assistant Inspectors General in the seven zones of the police formation is in an interface dialogue with the traditional and community leaders in Jos to chart a way forward to end violent clashes.
When contacted, the Police Public Relations Officer for Plateau State, Abu Emmanuel, said he was yet to confirm the incident.