Facebook also said it would search for and remove content praising the storming of the Capitol or encouraged violence.
Twitter has suspended more than 70,000 accounts since Friday that were primarily dedicated to sharing QAnon content after last week’s violence in Washington when supporters of President Donald Trump stormed the US Capitol.
QAnon backers have pushed conspiracies on social media that include the baseless claim that Trump secretly is fighting a cabal of child-sex predators, among them prominent Democrats, figures in Hollywood and “deep state” allies.
“Given the violent events in Washington, DC, and increased risk of harm, we began permanently suspending thousands of accounts that were primarily dedicated to sharing QAnon content on Friday afternoon,” Twitter said in a blog late on Monday.
“These accounts were engaged in sharing harmful QAnon-associated content at scale and were primarily dedicated to the propagation of this conspiracy theory across the service.”
Twitter said on Friday it would permanently suspend accounts pushing QAnon content, banning prominent right-wing boosters of its conspiracy theories.
The storming of the Capitol building last week by Trump supporters delayed the certification of Biden’s election victory.
Lawmakers were forced to flee, as the building was mobbed by the president’s supporters who overwhelmed security forces. Five people died in the violence including one Capitol Police officer who was beaten as he tried to ward off the crowds.
On Monday, a planned protest outside Twitter’s San Francisco headquarters against the social media platform’s ban of Donald Trump fizzled out when just a handful of the US president’s supporters turned up.
Messages posted this weekend on popular far-right forum TheDonald.win had called on pro-Trump activists to assemble outside the tech giant’s offices, which are largely deserted as staff work from home due to the pandemic.
One user even urged participants to bring zip ties to “citizen arrest violent agitators,” the San Francisco Chronicle reported.
Police deployed dozens of officers and constructed security barriers, but only a few protesters and counter-protesters arrived.
“I don’t like being censored. And I feel conservative voices are being censored,” one protester told the local Fox television station KTVU.
Kenneth Lundgreen, 71, told the Chronicle he wanted to “act as a counter balance” in case a crowd like the one that stormed the US Capitol in Washington, DC last week arrived.
Shortly after that unrest, Twitter imposed a permanent ban on Trump’s account – which had 88 million subscribers – prompted by multiple violations of its rules and the risk of “further incitement of violence”.
Trump accused the company of conspiring with the “Radical Left,” while some international leaders including German Chancellor Angela Merkel have called the ban “problematic.”
Other platforms including Facebook and Snapchat also have suspended Trump.
US Democrats have launched the process of impeaching Trump for a historic second time for “incitement of insurrection” over the attack on the Capitol, in which five people died.