One person is dead and several others are in hospital after a fire broke out inside a lowrise Toronto Community Housing Corp. building Thursday evening.

The fire broke out inside a fourth-floor apartment at around 5:45 p.m. and quickly became a three-alarm blaze. The flames were extinguished a short time later but authorities said one person had died and several others were taken to a local hospital for treatment.

Captain David Eckerman said when emergency crews arrived on the scene, they were able to see flames coming from the fourth floor and people hanging off their balconies. Emergency crews received calls from people who said they were trapped and needed help getting out but residents were being told to stay inside their unit as heavy smoke filled the halls.

Twelve people were rescued with the help of aerial ladders set up by fire crews. At the height of the fire, nine fire trucks were on the scene.

Four patients have been transported to hospital, all with minor injuries.

The tenant rep for the building, Conrad Hall, said he saw a few tenants on the ground floor, some of whom have mobility issues. He said firefighters were able to clear the building but most people on the fourth and fifth floor took shelter inside their aparments.

About 150 people live in the five-floor housing complex but none of them will be able to return this evening.

Toronto Mayor John Tory was on the scene and told reporters that residents would be put up in hotels as the building wasn't deemed safe for people to immediately return.

He said he didn't know when people might be able to return home.

The Fire Marshal's Office is investigating the circumstances around the fire but the TCHC will also conduct their own investigation.

In the meantime, Hydro crews shut off power to the building. Authorities said as a result, electricity could be shut off in other parts of the neighbourhood.