After years of pressure to crack down on extremist content, Facebook has banned Louis Farrakhan, Alex Jones and other extremists, saying they breached its ban against hate and violence.
The company also banned right-wing activists Paul Nehlen, Milo Yiannopoulos, Paul Joseph Watson and Laura Loomer, along with Mr Jones's site, Infowars.
The latest bans apply to Facebook's main service and Instagram, as well as fan pages and other related accounts.
Decried as censorship by several of those whose accounts were deleted, the move signals a renewed effort by the social media company to remove objectionable material and people who promote hatred, racism and anti-Semitism.
Removing some of the best-known figures of the US political extreme takes away an important voice that Facebook has given the likes of Mr Jones and Mr Yiannopoulos over the years.
Anti-racist activists praised the move but said there was more to be done on both Facebook and Instagram.
"We know that there are still white supremacists and other extremist figures who are actively using both platforms to spread their hatred and bigotry," said Keegan Hankes of the Southern Poverty Law Centre, which tracks hate groups in the US.
Facebook previously suspended Mr Jones temporarily. This suspension is permanent. The company said the banned accounts breached its policy against dangerous people and organisations.
The company said it had always banned people or groups that proclaim a violent or hateful mission or are engaged in acts of hate or violence, regardless of their political leanings.
Two weeks ago, the platform banned British far-right organisations and their leaderships, including the English Defence League, Britain First and the British Nationalist Party.
It said the groups contravened its policies against hate and incitement of violence.
For years, social media companies have been under pressure from civil rights groups and other activists to clamp down on hate speech on their services.
After the deadly white nationalist protests in Charlottesville, South Carolina, in 2017, Google, Facebook and PayPal began banishing extremist groups and people who identified as or supported white supremacists.
A year later, widespread bans of Mr Jones and Infowars were a more aggressive enforcement of policies against hate speech.
But Facebook instituted just a 30-day suspension, although Twitter banned him permanently.
It is not clear what events led to Thursday's announcement.
"The process for evaluating potential violators is extensive and it is what led us to our decision to remove these accounts today," Facebook said.
Last month, the company extended its ban on hate speech to prohibit the promotion and support of white nationalism and white separatism. It had previously allowed such material even though it has long banned white supremacists.
Asked to comment on the bans, Mr Yiannopoulos emailed only: "You're next."
Mr Jones reacted angrily Thursday during a live stream of his show on the Infowars website.
"They didn't just ban me. They just defamed us. Why did Zuckerberg even do this?" Mr Jones said, referring to Facebook chief executive Mark Zuckerberg.
Mr Jones called himself a victim of racketeering by cartels.
"There's a new world now, man, where they're banning everybody and then they tell Congress nobody is getting banned," he said.
Mr Watson, meanwhile, tweeted that he was not given a reason and that he "broke none of their rules".
"Hopefully, other prominent conservatives will speak out about me being banned, knowing that they are next if we don't pressure the Trump administration to take action," he wrote.