Officials said a group of unidentified armed men entered the government girls' primary school in Nawagai tehisl of Bajaur agency and rigged the building with explosives.
The gunmen later triggered a blast, razing the school building, they said.
No loss of life was reported during in the incident.
Residents of the area and volunteers of village defence committee reached the spot soon after the incident and cordoned-off the area.
Meanwhile, local authorities have arrested several people suspected of involvement in the crime during a search operation in the area.