GILLETTE, Wyo. (AP) — Investigators say two children may have started a grass fire that threatened several structures in northeast Wyoming.

The fire Monday burned two-thirds of a square mile in the Gillette area. No homes or other buildings burned.

Police Lt. Chuck Deaton says two girls ages 11 and 12 told investigators they used hairspray and a cigarette lighter to burn a sweater.

The girls said they poured water and stomped on the flames before leaving the sweater outside.

Deaton says it's not known yet whether the girls started the fire.