A wildfire burning in the Whetstone Mountains southwest of Benson grew to about 650 acres Wednesday.

The lightning-sparked fire began Monday near Cottonwood Peak.

The Cottonwood Fire is burning in grass, brush, oak, juniper and pinyon pine, according to the Coronado National Forest.

Crews focused on stopping the fire's westward progress toward Cottonwood Peak, forest officials said in a news release.

The fire started burning to the east and south, forcing crews to construct a fire line and burn out areas near the blaze to prevent its progress.

About 170 people are assigned to the fire. There are six crews assigned, along with three engines and two water tenders. Two helicopters are also being used.

No structures were threatened Wednesday, and no evacuations were ordered.