Twitter has removed more than 7,000 accounts linked to the "QAnon" movement over abuse and harassment concerns, and promised to try limiting the spread of conspiracy theories by its supporters.
Members of the informal, pro-Donald Trump group believe – with no credible evidence – that the United States has been ruled for decades by a criminal organisation involving people they describe as the Satan-worshipping global elite, including Hollywood stars and the "deep state".
But crucially, they believe there is a senior insider with access to classified information drip-feeding revelations about the cabal and Mr Trump's war against them in a semi-coded format through online posts to 4Chan, a message board popular with the far-right.
Believers in QAnon have targeted Mr Trump's political opponents, a raft of celebrities and other high profile figures on social media with harassment.
"We've been clear that we will take strong enforcement action on behaviour that has the potential to lead to offline harm," Twitter said.
"In line with this approach, this week we are taking further action on so-called 'QAnon' activity across the service," it said.
"We will permanently suspend accounts tweeting about these topics that we know are engaged in violations of our multi-account policy, co-ordinating abuse around individual victims, or are attempting to evade a previous suspension."
A spokesperson said the social media giant had decided to act because QAnon followers were causing increasing harm.
The FBI has identified QAnon as a potential domestic terrorism threat, according to US media.
QAnon members have recently been involved in protests against measures to combat the spread of the coronavirus, especially lockdowns and face masks
Twitter said it would help stop the spread of QAnon conspiracy theories by, among other things, making sure the Twitter algorithm does not highlight sites and tweets associated with their accounts.
It will also "block URLs associated with QAnon from being shared on Twitter."
About 150,000 accounts will also be hidden from trends and search on Twitter, a spokesperson said.
Supporters of the group claim that "Q" or "QAnon" is a mole in the president's inner circle who has decided to reveal titbits of intelligence concerning the global conspiracy on fringe internet platforms.
While it originated on the edges, QAnon has built a growing following on mainstream social media platforms too. Some QAnon adherents are even running for Congress this November.
Twitter's decision comes after nearly 1,000 advertisers announced they were boycotting Facebook, demanding more aggressive action against content that promotes violence and hate.
In April, Facebook removed 20 accounts, five pages and six groups linked to QAnon.
