Edmonton -- Some 480 firefighters in the western Canadian province of Alberta were battling at least 22 out-of-control wildfires Tuesday, officials said.

Dry weather conditions, lightning strikes and sparks from campfires were among the causes of the fires, the largest of which was burning near Fort McMurray, 270 miles northeast of Edmonton, the Edmonton Journal reported.

That fire had consumed more than 5,600 acres by Tuesday morning, officials said.

Various highways were closed throughout the province as flames approached or smoke reduced visibility to zero, the report said.

Wildlife information officer Anastasia Drummond told reporters there have been 861 forest fires since April 1, which is up 20 percent from the five-year average.

Drummond said a call has gone out for 175 firefighters from other provinces to help with the effort that has 22 tanker aircraft and 65 helicopters dropping water and foam.

She said more than 56,800 acres of woodland have been consumed by fire, the Canadian Broadcasting Corp. reported.

There have been no reports of injuries of building losses, the reports said.