Faisalabad police have arrested a student for his involvement in a cracker attack inside the school on Thursday.
The blast panicked other students and faculty of the higher secondary school in Dijkot area as they struggled to take refuge, thinking it was a terrorist attack.
Educational institutions are on alert following a January 20 terrorist attack on Bacha Khan University in Charsadda district of Khyber Pakhtunkhwa, which left 22 people dead.
Police have arrested 16-year-old Muhammad Azeem, a student of the school, a police spokesperson said.
According to the SHO, facts were being ascertained to decide a future course of action against the student.
Confirming the incident, Principal Muhammad Tufail said the student had been reprimanded for his act, which did not appear to have a terror-related motive.
In a similar incident in Karachi on February 12, five students were found to have been involved in a cracker attack outside a school in North Nazimabad area.