Police and local officials on the West Coast are battling multiple raging fires. They’re also fighting a wave of misinformation from false rumors spread in neighborhood Facebook groups and on far-right websites that antifa activists were setting the blazes.At least six groups have issued warnings about the false rumors, including some pleading with the public to stop sharing the misinformation.“Rumors spread just like wildfire and now our 9-1-1 dispatchers and professional staff are being overrun with requests for information and inquiries on an UNTRUE rumor that 6 Antifa members have been arrested for setting fires in DOUGLAS COUNTY, OREGON,” the Douglas County Sheriff’s Office wrote in a Facebook post on Thursday.The false claims also became fodder for the now-sizable online QAnon community, which began amplifying various false reports earlier in the week.Read more from NBC News:COVID-19 has killed dozens of 9/11 first responders7 deaths confirmed as wildfire rages in Northern California; at least 12 dead in stateDemocrats are nervous about Trump’s persisting edge over Biden on the economyThe sheriffs in Jackson County, Oregon, and Mason County, Washington, posted similar warnings, begging locals to stop spreading unsubstantiated claims.A firefighters union in Washington state called Facebook “an absolute cesspool of misinformation right now,” in a post that sought to quell more rumors about the fires’ origins.Antifa has emerged in recent months as the focal point of far-right paranoia, fueled by evidence-free accusations from President Donald Trump and other government officials that the loosely knit anti-fascist organizations that make up antifa are behind everything from violence during protests to plots to invade suburban neighborhoods.The Medford police debunked the antifa rumor along with a separate, less viral false claim that the fires were a result of arson by the Proud Boys, a far-right group whose members describe themselves as “western chauvinists” and have been an antagonistic mainstay of Black Lives Matter protests.A fire in Ashland, Oregon, is being investigated as arson, but The Oregonian reported Ashland Police Chief Tighe O’Meara as saying, “One thing I can say is that the rumor it was set by Antifa is 100% false information.”The dozens of fires burning across California, Washington and Oregon, which have killed at least 20 people, started in a variety of ways, mostly by people, though not intentionally. Lightning, faulty or knocked-down power lines and accidents, like the El Dorado fire in California ignited by a pyrotechnic device during a “gender-reveal party,” are some of the reported causes of this year’s wildfires.Despite protestations from law enforcement, rumors have spread through far-right Facebook groups and news websites like Gateway Pundit and the Post Millennial in stories alleging without evidence that Jeff Acord, a 36-year-old man arrested on charges of starting a fire in Puyallup, Washington, was an “antifa militant.” The Post Millennial later changed the story to call Acord a “BLM activist.”Some articles that have pushed misinformation about the fires have gained traction on Facebook.An article from the far-right website Law Enforcement Today claimed without evidence that the wildfires were a “coordinated and planned” attack. It attracted more than 330,000 comments, likes and shares on Facebook, according to data from CrowdTangle, a Facebook-owned social media analysis tool. Late Thursday night, Law Enforcement Today topped the story with an update stating that “suggestions that Antifa members have been arrested are unfounded,” but left the article up.In response to fact checks debunking the antifa rumors, Facebook was “reducing its distribution and showing strong warning labels for people who see it, try to share it, or already have,” according to Facebook spokesperson Andy Stone.One of the earliest claims of antifa involvement came from Paul Romero, a former Republican candidate for U.S. Senate in Oregon, who said in a viral tweet that Douglas County police had arrested six antifa arsonists. Romero stood by his tweet in a phone interview on Thursday, calling the fires a “coordinated intentional attack,” by antifa but providing no evidence for the claim, saying he heard about the arrests from “sheriff’s deputies that have been talking.”Romero’s post was further spread by followers of QAnon, a conspiracy movement based on the idea that Trump is leading a secret war against a group of political, business and Hollywood elites who, the theory posits, worship Satan and murder children. The leader of the movement, an anonymous figure who posts to a message board as “Q,” included Romero’s tweet in a post early Thursday.Some users responding to Romero’s posts said they were sent there by Q and pushed false QAnon talking points that the fires were part of an elaborate political plot. According to data gleaned from the disinformation analytics tool Hoaxy, most of the traffic to Romero’s post came after Q’s post, almost a full day after Romero had posted it.Antifa, a loose network of autonomous groups of radicals who rely on direct action rather than the police or the court system to shut down the far right and perceived fascism, has been increasingly blamed for unrest during Black Lives Matter protests and become the subject of unfounded rumors that the group would arrive in white suburbs by the busload to loot homes and destroy town centers. Those false rumors have often led to standoffs between local Black Lives Matter protesters and armed militias who come to guard their towns from a suspected mob that never arrives.Justin Yau, an independent journalist covering the fires, tweeted on Thursday from Molalla, Oregon: “We were approached by an armed group telling us to leave, they are wary of outsiders based on rumors of arsonists starting fires in the area.”In May, Trump tweeted that he would designate antifa as a terrorist organization and has made the group a major target in campaign ads and texts since. “ANTIFA THUGS WILL RUIN SUBURBS!” the Trump campaign texted supporters on Thursday.Subscribe to CNBC on YouTube.