Hundreds of firefighters battled a massive wildfire in western Canada for a 10th straight day Tuesday as federal police launched a criminal investigation into the cause of the blaze.

The fire on the shores of Little Bobtail Lake, about 800 kilometers north of Vancouver, nearly doubled in size over the weekend, scorching 25,000 hectares as well as forcing the evacuation of 80 people and threatening 700 residences, according to officials.

More than 300 firefighters, heavy equipment and a dozen helicopters have been sent to the remote region to try to douse the flames but have so far managed to keep the fire only 15 percent contained, Melissa Klassen of British Columbia Wildfire Management Branch told AFP.

The Royal Canadian Mounted Police, meanwhile, announced that the fire may have been set. The federal police force is awaiting the results of forensic tests to determine if criminal charges may be laid.

RCMP Corporal Craig Douglass said the fire started in the middle of a forest, off of a forestry service road.

"There was enough indication at the scene to lead us to believe that it could be human-caused," he said.

No suspect has been publicly identified.