Toronto fire are investigating after a three-alarm blaze in a North York apartment left a man critically injured on Friday.

Emergency crews said they were called just before 6 p.m. to an apartment building in the area of Parkwoods Village Drive and York Mills Road.

When firefighters arrived, they were encountered heavy smoke billowing out of a unit in the fifth floor of the building, Capt. David Eckermann said.

He said fire crews entered the unit and quickly knocked down the main body of the fire.

Following a search, firefighters located one person in the balcony with injuries.

Toronto paramedics said the victim has been taken to hospital in life-threatening condition.

Several people were assessed by paramedics for minor smoke inhalation.

The fire reached a third-alarm response due to smoke migration inside the building.

The cause of the fire is unknown.

Toronto fire investigators and the Office of the Fire Marshal have been called to investigate.