A woman in her 80s is dead after a two-alarm fire tore through a condo building in Toronto’s Leaside area overnight.

Firefighters were called to 955 Millwood Road, near Southvale Drive, before 1 a.m. for a report of a fire.

"Our crews were met with heavy smoke in the hallway and a significant fire in the unit," Chief Jim Jessop told reporters Wednesday morning.

They pulled a woman from a unit and observed thick black smoke in the hallways.

The blaze reached two alarms but was eventually put down.

Toronto paramedics said they rushed a woman in her 80s to a hospital trauma centre in life-threatening condition.

Fire Chief Matthew Pegg said the woman died sometime later.

Paramedics were seen performing chest compressions on the woman in the back of an ambulance before it departed.

The cause of the fire is unknown.

"The investigation into this fire has commenced with Toronto Fire Service, Toronto Police and the Office of the Ontario Fire Marshal and that investigation will take a number of days to try to determine the origin, cause and circumstances of this fire," Jessop said.

The fire was contained to the one unit and the rest of the building remains habitable, Jessop said.

TTC shelter buses were brought for residents who had to evacuate.

Police closed Millwood Road between Southvale Drive and Randolph Road to give emergency crews room to operate.