Facebook expected a fresh onslaught of disinformation from the Kremlin ahead of the midterms. Instead, the company revealed this week the greater threat has originated from within the U.S.

Facebook said Thursday it was shutting down close to 800 U.S.-based pages and accounts, some of which have millions of followers, for spamming users with biased politically-oriented content that violates the network’s policies.

“Today, we’re removing 559 Pages and 251 accounts that have consistently broken our rules against spam and coordinated inauthentic behavior,” the company said in a blog post. “People will only share on Facebook if they feel safe and trust the connections they make here.”

Facebook added that there is no indication any of the accounts are linked to Moscow.

An investigation published earlier this week by The Daily Beast cited numerous researchers who said they were surprised by the lack of disinformation being spread by Russia’s Internet Research Agency ahead of November’s vote.

Facebook said the banned accounts used clickbait headlines that were often posted hundreds of times in dozens of different groups, and were designed to drive users to external ad farms.

In the past, this type of activity has focused on topics such as natural disasters or celebrity gossip, but today the focus is increasingly on sensational political content.

Facebook said that often it is hard to distinguish the “news” shared by clickbait sites from legitimate political debate.

The company only gave five examples of the removed pages, including Right Wing News, which has more than three million followers, and recently peddled fake stories about Christine Blasey Ford as she testified about her alleged sexual assault by Supreme Court Justice Brett Kavanaugh.

But it wasn’t just conservative voices that were silenced. The left-leaning Reasonable People Unite page was also shut down. Its administrator, Chris Metcalf, told the Washington Post that he was confused by Facebook’s decision.

“I am a legitimate political activist. I don’t have a clickbait blog. I don’t have a fake news website. And I haven’t been doing anything that all the other pages in this space aren’t doing,” Metcalf said.

Dan Dicks, whose account boasting 350,000 followers was also banned, warned that Facebook’s decision was a threat to free speech. “There is a dangerous precedent being set here where the big tech companies have appointed themselves as the gatekeepers of political thought and opinion.”

The Free Thought Project, a website that peddles conspiracy theories, was also angry at Facebook’s decision.

“After 5 years of building fans Facebook has officially unpublished our page (3.1 million fans) so we can't post on it anymore. This is truly an outrage and we are devastated. We will do everything we can to recover our page and fight back,” the site said on Twitter before that account was also banned.