By Elizabeth Culliford
(Reuters) - Several Oregon police departments have aimed to debunk misinformation spreading on social media platforms this week, including Facebook Inc <FB.O> and Twitter Inc <TWTR.N>, blaming leftist and right-wing groups for wildfires raging in the state.
"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," read a Facebook post from the Douglas County Sheriff's Office in Oregon on Thursday. "THIS IS NOT TRUE!"
PolitiFact, one of Facebook's third-party fact-checking partners, wrote on Thursday on its website that dozens of posts blaming antifa for the wildfires had been flagged by the social media company's systems, and that collectively the posts had been shared thousands of times.
Antifa, which stands for anti-fascist, is a largely unstructured, far-left movement whose followers broadly aim to confront those they view as authoritarian or racist. U.S. President Donald Trump and some fellow Republicans have in recent months sought to blame the movement for violence at anti-racism protests, but have presented little evidence.
A Wednesday tweet from a self-described representative for conservative youth group Turning Point USA, which has been shared about 2,900 times, said the fires were "allegedly linked to Antifa and the Riots."
Around half a million people in Oregon evacuated as dozens of extreme, wind-driven wildfires scorched the U.S. West Coast states on Friday, destroying hundreds of homes and causing at least 24 deaths, state and local authorities said.
Earlier this week, Medford police in Oregon also debunked a false post using the police department's logo and name suggesting that five members of the Proud Boys had been arrested for arson.
The men-only, far-right Proud Boys group describes itself as a fraternal club of "Western chauvinists."
"This is a made up graphic and story. We did not arrest this person for arson, nor anyone affiliated with Antifa or 'Proud Boys' as we've heard throughout the day," the police department wrote in a Facebook post.
The Jackson County Sheriff's Office in Oregon also posted on Thursday: "We are inundated with questions about things that are FAKE stories. One example is a story circulating that varies about what group is involved as to setting fires and arrests being made."
Climate scientists say global warming has contributed to greater extremes in wet and dry seasons, causing vegetation to flourish and then dry out in the U.S. West, creating fuel for fires.
Police have opened a criminal arson investigation into at least one Oregon blaze, the Almeda Fire, Ashland Police Chief Tighe O'Meara said.
A Facebook spokeswoman said it had attached warning labels and reduced the distribution of posts about fires' origins that were rated false by its fact-checking partners.
A Twitter spokeswoman said it did not seem that the rumors violated the social media site's rules, saying in a statement: "As we have said before we will not be able to take enforcement action on every Tweet that contains incomplete or disputed information."
(Reporting by Elizabeth Culliford in Birmingham, England, additional reporting by Katie Paul in San Francisco; Editing by Tom Brown)