YARNELL, Ariz. -- A brush fire threatened structures early Thursday in the north-central Arizona town of Yarnell - the scene of a 2013 wildfire in which 19 members of an elite firefighting crew were killed.

Some residents on the town's east and west sides were told to evacuate their homes as a precaution, Yavapai County sheriff's spokesman Dwight D'Evelyn said. CBS Phoenix affiliate KPHO-TV reports 250 homes had been evacuated as of late Wednesday night and more than 1,000 houses and businesses were without power.

D'Evelyn said no injuries have been reported.

Three outbuildings had been burned in the blaze -- dubbed the Tenderfoot Fire -- which was estimated at 600-700 acres, KPHO says.

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Dolores Garcia, a spokeswoman for the Bureau of Land Management, said there was no lightning in the Yarnell area Wednesday and the cause of the fire was under investigation.

It was burning south of the town and east of the site of the Yarnell Hill Fire in which members of the Granite Mountain Hotshots died when they got trapped by the flames nearly three years ago - the deadliest U.S. tragedy for wildland firefighters in several decades. It was the largest loss of life for U.S. firefighters since the Sept. 11 terrorist attacks.

That lightning-caused wildfire destroyed nearly 130 homes in the area.

On Wednesday, some Yarnell homeowners said they saw smoke and received a voluntary evacuation notice on their cellphones.

A Red Cross shelter for evacuees was set up at Yavapai College in Prescott.

"We're praying our houses don't go again," Yarnell resident Jane Sanderson told KPHO. She was packing up and preparing to evacuate. "We just want everybody to be safe and have our homes safe and trust that our firefighters will be safe also."

Highway 89 through Yarnell was shut down as U.S. Forest Service crews did back-burns and dug trenches while air tankers dropped slurry loads before nightfall.

Authorities said the fire appeared to be moving up mountain slopes to the northeast of Yarnell and away from the town, but its western flank still was threatened.