The Ganga Academy High School was set ablaze in Sugnu area, about 65 km south-east from here, at around 4 am yesterday and the flames gutted major portion of the building.
There was no report of any injury or casualty, they said.
Even though identity of the troublemakers was not yet known, the incident came against the backdrop of similar attacks on school buildings during past two weeks.
All Manipur Students Union (AMSU), Manipur Students' Federation (MSF) and Kangleipak Students' Association have been boycotting classes since September 9 to support the demands of a major social organisation, Apunba Lup (AL).
The outfits have warned the educational institutions not to conduct classes during the boycott call.