Authorities in the United States said on Sunday that at least six people were injured and 42,000 were ordered to evacuate as a fast-moving wildfire spread rapidly toward Reno, a city in northwestern Nevada near the Nevada-California border.

The Hawk Fire, which began on Saturday, has grown to more than 53 square kilometers so far and remained completely uncontained, fire officials said at a news conference on Sunday.

Officials added that the injured included three civilians and three first responders, and an additional 45,000 people were in the evacuation warning zone.

They also confirmed that several structures have been destroyed in the fire.

About 10,000 customers were without power in Washoe County on Sunday. Reno is the county seat and most populous city of Washoe County.

Officials said that extreme fire behavior has been observed, with wind-driven fire making significant runs through light, flashy fuels.

Nevada Governor Joe Lombardo declared a state of emergency for Washoe County on Saturday night.

"This is an active and rapidly evolving situation, and I urge everyone in the affected areas to remain vigilant and follow the direction of local officials," Lombardo said in a statement. "The state is fully engaged, and we are working alongside local authorities and first responders to deploy every available resource to protect lives, safeguard communities, and keep Nevadans out of harm's way."

The governor warned again on Sunday morning on social media that the fire is still "a rapidly evolving situation."

"Stay vigilant and keep yourself informed if you are in the affected areas," the governor said.