The Ontario Fire Marshal has been called to investigate a two-alarm fire at a construction site in the Junction.
Fire crews were called to High Park Avenue and Annette Street just after 11:30 p.m. on Friday.
No injuries were reported in the blaze, which happened at an old church being converted into condos.
Toronto police say a 9-1-1 caller reported someone running away after the flames broke out, but would not indicate whether the blaze is being investigated as possible arson.
A damage estimate has not been made available.
Area roads were closed as the fire crews worked on the scene, but have since re-opened.