A stretch of Yonge Street in downtown Toronto is closed due to a three-alarm fire at a commercial building on Sunday morning. Toronto Police said they were called to the area of Yonge and Elm streets just after 6 a.m. Toronto Fire Services (TFS) said their crews responded for a fire on the roof of 359 Yonge St. and saw heavy black smoke when they arrived. Zanzibar Tavern, an adult entertainment club is located at that address. “Crews are actively fighting fire with areas of the structure now deemed compromised,” TFS said in a post on social media. Fire services said the roof has become unstable as a result of the fire, which became unsafe for their crews combatting the fire from inside. Police said there are unknown injuries at this time. The circumstances surrounding the fire are unknown at this time. Yonge Street is closed between Dundas and Gerrard streets, police said, as well as westbound Gerrard Street at Church Street. TFS said they are continuing to fight the fire from outside, as there are still hot spots. It is unclear how long it will take to completely extinguish the flames.