ELY, Minn. (AP) - Crews are working from the ground and air to try to stop a prescribed fire that escaped from its containment lines in the Superior National Forest west of Ely.

The U.S. Forest Service says the fire crossed the lines at 2 p.m. Thursday, escaping to the north and west of Foss Lake.

Reports say the fire is about 10 miles west of Ely and three miles north of Highway 169.

Air tankers, helicopters, and additional ground firefighters are responding.

The size of the fire was not immediately determined. Firefighters had planned to burn 78 acres to reduce hazardous fuels on the ground and improve habitat for oaks and blueberries.