Aircraft were pulled off a wildfire burning a half-mile northwest of Bisbee in southeastern Arizona after crews reported Monday evening that the blaze was 40 percent contained.

Twenty homes remained evacuated as a precaution, but firefighters allowed people to return to 10 other homes that had been evacuated.

The fire was burning away from the town and had scorched about 180 acres.

Crews expected the blaze to continue burning away from the town.

No homes have been burned.

The cause of the fire, first reported around midday Monday, was unknown.

State forestry spokeswoman Judy Wood said crews initially attacked the blaze with 10 air tankers and 10 to 15 fire engines, an unusually strong offensive because of the fire's proximity to Bisbee.