President Donald Trump listens to a question as he speaks with reporters on the South Lawn of the White House, Wednesday, June 26, 2019, in Washington. Credit: Alex Brandon | AP

The biggest forum for supporters of President Donald Trump on Reddit has been “quarantined” following months of incitements to violence and other offensive behavior, the tech giant said Wednesday, in a move that could further inflame conservatives’ claims of social-media bias.

The forum, called “r/The_Donald,” has long served as a highly trafficked and controversial gathering place for supporters of Trump and Republicans on Reddit, America’s fifth-most popular website.

Created in 2015, “The_Donald” counts roughly 750,000 followers and advertises itself as “a never-ending rally dedicated to the 45th President of the United States, Donald J. Trump.”

Reddit officials said on Wednesday that the board had allowed or encouraged months of “rule-breaking behavior,” including the “encouragement of violence towards police officers and public officials in Oregon.”

“We are clear in our site-wide policies that posting content that encourages or threatens violence is not allowed on Reddit,” Reddit spokeswoman Anna Soellner said in a statement to The Washington Post. “We are sensitive to what could be considered political speech,” Soellner added, but “recent behaviors including threats against the police and public figures is content that is prohibited by our violence policy.”

The action will effectively demote the forum on Reddit, restricting how its content is shared across the site and removing key features. It is not an outright ban, but will conceal the forum behind a warning and require viewers to verify they are sure they want to view its contents.

Quarantines are rare punishments imposed on only the forums Reddit has deemed most offensive or upsetting. Past quarantines have included forums devoted to white supremacy, Sept. 11 conspiracy theories and videos of fatal violence.

The message board has long trafficked in edgy “trolling” and offensive behavior, promoting anti-Semitic memes and baseless conspiracy theories, including that victims of the Parkland school shooting were “crisis actors.”

Some of the top threads on “r/The_Donald” Wednesday criticized E. Jean Carroll, the author who recently accused Trump of rape, and called Megan Rapinoe, the U.S. soccer star whom Trump had criticized, a “human leech.”

Reddit is a link-sharing and discussion site where readers can submit and vote on posts; the most “upvoted” posts are promoted more widely across the site. The site’s forums, known as “subreddits,” operate independently from the company and are overseen by volunteer moderators, who are expected to follow sitewide rules banning violent threats, harassment and other prohibited content.

The forum’s moderators tweeted on Wednesday that the company had moved to “totally suppress” the forum “on the eve of the Democrat Debates.” In a post on the forum, the moderators said the company has “set up an impossible standard as a reason to kill us before the 2020 election.”

Forum moderators had in weeks past changed elements of the “subreddit,” removing the down-vote button and changing the “Report” button, which allows people to flag potential rule-breaking content, to say “Deport.”

The “quarantine” move comes on the same day Trump launched his latest attack against Silicon Valley. He threatened a potential lawsuit against Facebook and Google, without providing much detail, and accused Google of trying to rig the election. The company has repeatedly denied that claim.

Trump also accused Twitter of limiting the reach of his tweets and censoring other conservative users, a charge the tech giant has long denied. The White House on Wednesday also announced it would gather “digital leaders” next month to talk about social media but did not elaborate on who would be in attendance.

The White House did not immediately offer comment on the Reddit move.

The Washington Post’s Tony Romm contributed to this report.