A downtown highrise has been evacuated as firefighters continue to battle a six-alarm blaze at a apartment building on Wellesley Street on Friday evening.

The fire initially started before 5 p.m. on the 24th floor of the building at 200 Wellesley St., near Bleecker Street, and has now spread to other units on the 23rd floor.

Heavy black smoke can be seen from the balcony of an apartment in the building. Toronto Fire chief William Stewart says there was a high level of combustible materials in one apartment.

The building has been evacuated due to structural damage. Residents are being provided with shelter housing.

Up to 14 people, including three firefighters, have been taken to hospital. Three people are listed in serious condition.

There's 27 fire trucks and about 120 firefighters at the scene. The fire is believed to be contained to three units.

For more information, watch CP24.