A home north of Toronto sustained extensive damage after a fire broke out at a Thornhill home Friday afternoon, trapping two family pets in the basement.

The fire started at a home on Joanna Crescent, near the area of Yonge Street and Clark Avenue West, shortly before 1 p.m.

Firefighters arrived at the scene to find the home fully engulfed in flames. There have been no reports of any injuries, but the homeowner’s four pets were inside the house when the fire broke out.

Two dogs were able to escape on their own, but two other animals – a cat and another dog – were trapped in the basement. Fire crews were able to rescue the animals and they have been taken to a veterinarian as a precaution.

Aerial images of the fire showed the roof of the home nearly destroyed, with many of the beams showing. Officials believe the fire started at the back of the home near the patio doors, and quickly made its way inside the residence and before travelling up to the roof.

"It was fairly aggressive," Deputy Chief Gary Verdin told CTV Toronto at the scene. "It progressed into the home very quickly without any detection."

The home has been in John Houston's family for 30 years. He says his sister, who was at work when the fire started, lives alone with the animals.

"We have our whole life history in there," Houston said.

Police say it was neighbours who called 911.

"The whole house was in flames at the back and then we went to the back to look at it and the roof collapsed," one neighbour said.

It's not yet clear how the fire started. It was stamped out shortly before 4:30 p.m., but firefighters remained at the scene to put out a number of hot spots.

The Office of the Ontario Fire Marshall has been notified.

With a report from CTV Toronto's Zuraidah Alman