An underground electrical fire has caused a series of "explosions" in downtown Toronto.
Witnesses on social media said they heard what sounded like multiple explosions and saw billowing clouds of smoke coming from subway grates.
No injuries have been reported.
Toronto Fire Service confirmed that the fire began in an underground vault used to store electrical transformers.
Some buildings have been evacuated because of the smoke and police closed off the area near Bay Street and King Street but subway service have not been affected.
"You don't want to be in the smoke," Toronto Fire Services platoon chief Kevin Shaw said.
The blasts died down after a few minutes but a BBC reporter on the scene said they could still hear popping sounds "like popcorn" and smell acrid smoke in the air.
Mr Shaw said that the fire was "under control" and may have been triggered by damp weather.