A fire broke out on the roof of a high school in Thorncliffe on Tuesday night.

Toronto police were called to Marc Garneau Collegiate Institute at Don Mills Road and Overlea Boulevard, shortly before 8 p.m. 

The blaze may have been caused by ongoing construction on the roof, said Const. Jenniferjit Sidhu, a spokesperson for Toronto police. 

Construction workers were not on-site when the fire began. 

No one was injured by the blaze.

Crews extinguished the flames, but are continuing to monitor hot spots. 

Don Mills Road is closed in both directions at Overlea Boulevard.