However, a rescue worker from the agency put the death toll at 21 after four others died in hospital.
About 120 of the approximately 200 people who were in the building at the time of the collapse are believed to be trapped, Plateau Information Commissioner Musa Ashoms said in a statement.
“To ensure immediate medical care, the Government has ordered hospitals to prioritise treatment without documentation or payment,” Ashoms said.
“We heard a loud noise and ran outside to see that the school building had collapsed (...) Many students and teachers are still trapped under the rubble,” Peter Auta, a resident who witnessed the events, told media.
Emergency workers are continuing to search for survivors.
Building collapses are common in Nigeria - Africa’s most populous country with more than 213 million people - a problem attributed to the use of substandard building materials and negligent inspections of properties by authorities.
In November 2021, at least 45 people died when a 21-storey building under construction collapsed on the outskirts of Lagos, Nigeria’s largest city and economic capital.