CHEYENNE, Wyo. (AP) — Nearly 300 firefighters are battling a wildfire burning in remote and mountainous area of the Medicine Bow National Forest.

The crews at the Russell's Camp fire Wednesday include those who are trained in fighting fires in rugged terrain and capable of sustaining themselves in remote areas.

The fire is located about 30 miles south of Glenrock in Converse County and has burned about 4 square miles since Sunday.

There is no containment yet and the cause of the fire is still under investigation.

About 40 residents of widely scattered ranches and summer cabins in the area were advised to evacuate Monday afternoon.