As firefighters make significant progress against a massive blaze in Northern California, officials are warning those in areas affected by the wildfire to be on alert for bad actors posing as first responders looking to take advantage of the situation.

The California Department of Forestry and Fire Protection officials said Thursday that firefighting crews working through the night against the Kincade Fire in the state's wine country have increased their control of the blaze to 60 percent containment.

The fire started last week near the town of Geyserville in Sonoma County north of San Francisco and has scorched about 120 square miles. It has destroyed 141 homes and threatens 90,000 structures.

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Officials on Wednesday advised firefighters on the front lines to be aware of people posing as first responders.

"We did get a report yesterday of there’s possibly some fake firefighters out there, wanting to do some looting," Sonoma County Sheriff's Lt. Shawn Murphy told firefighters gathered at the fairgrounds in Santa Rosa for a morning briefing on Wednesday, according to KTVU.

"I’m sure you guys don’t want that, right? You don’t want a couple of idiots to ruin your outstanding reputation," Murphy said. "So if you see them, please report them to us, check their credentials, let’s get those guys out of here.”

Shaun Brewer, who was evacuated from her home told KTVU on Wednesday she might ask for identification and a badge before assuming she's talking with a real firefighter.

"Normally, I would trust a firefighter and security in a heartbeat," Brewer told KTVU. "So anybody pretending to do that, that's just total fraud."

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Other evacuees at a Red Cross shelter in Santa Rosa voiced similar concerns, saying that large disasters make them feel vulnerable to criminals.

"They're taking advantage, knowing that first responders, police, everyone, is so busy and it's very disheartening," Jennie Cormie of Santa Rosa told KTVU.

Officials advise residents that if they are in doubt if someone is a legitimate first responder to check for proper identification or ask to speak to a supervisor just to be careful.

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The overall weather picture in northern areas of California is improving as powerful, dry winds bring extreme fire weather to Southern California. The change in conditions up north has allowed firefighters to get a better hold on the Kincade Fire.

Pacific Gas & Electric, which has staged three sweeping blackouts this week, restored power to hundreds of thousands of people Wednesday and expected to have it back for the others sometime Thursday.

The Associated Press contributed to this report.