HAMPTON (AP) — Fire crews are battling rugged terrain and extreme heat as they take on a small wildfire on a remote mountain slope in East Tennessee, officials said.

U.S. forestry officials said the fire on Little Pond Mountain near Watauga Lake in Cherokee National Forest has burned 5 acres.

Crews have built indirect fire lines to try to stop the blaze, located about 7 miles south of Hampton in Carter County.

Smoke may be visible from the lake and surrounding communities, but no structures were threatened, the U.S. Department of Agriculture Forest Service said in a news release distributed Tuesday by the Tennessee Wildlife Resources Agency.

A helicopter, a bulldozer and a 20 person crew from the North Carolina State Forest Service have been assigned to the fire, officials said.

The cause of the fire is not known. It was first reported Saturday to the Forest Service.