A huge wildfire has prompted the evacuation of an entire Canadian city.

The population of Fort McMurray, Alberta - around 80,000 people - was ordered to evacuate as the blaze spread.

Some residents with medical problems may be airlifted out, Alberta Premier Rachel Notley said, adding that everything was being done to ensure people's safety.

She said: "This is the biggest evacuation we have seen in the history of the province in terms of fire."

There were no initial reports of any injuries as a result of the fire.

The blaze, which started southwest of Fort McMurray, spread rapidly on Tuesday to the outskirts of the city.

Canadian Prime Minister Justin Trudeau tweeted that he had offered the Government's support to the city, which is in the heart of Canada's oil sands region.

Nine air tankers, more than a dozen helicopters and over 100 firefighters have been battling the fire.

A number of buildings have been hit by the inferno, but it is not clear how many.

Stronger winds forecast for Wednesday are expected to make firefighting even more challenging.