Facebook banned President Donald Trump from the platform "indefinitely" due to his efforts to incite violence at the US Capitol, chief executive Mark Zuckerberg said Thursday.

Zuckerberg said the 24-hour ban announced Wednesday on Trump's accounts including on Instagram was extended because of Trump's "use of our platform to incite violent insurrection against a democratically elected government."

The Facebook CEO added: "The shocking events of the last 24 hours clearly demonstrate that President Donald Trump intends to use his remaining time in office to undermine the peaceful and lawful transition of power to his elected successor, Joe Biden."

The announcement came the day after the outgoing US leader was locked out of all major social media platforms due to his false claims about the legitimacy of his loss to Biden, and for inciting the angry mob that stormed the US Capitol.

"We believe the risks of allowing the president to continue to use our service during this period are simply too great," Zuckerberg wrote on his Facebook page.

"Therefore, we are extending the block we have placed on his Facebook and Instagram accounts indefinitely and for at least the next two weeks until the peaceful transition of power is complete."

Trump's favorite megaphone, Twitter, blocked him for 12 hours after making him remove rule-breaking tweets.

Twitter said Thursday that while the suspension was over, it was "continuing to evaluate the situation in real-time, including examining activity on the ground and statements made off Twitter" to determine whether more enforcement action is warranted.

Twitter has raised the specter of permanently banning Trump if he continues with posts lying about election results or inciting violence.

There were no new posts at Trump's Twitter account as of 2.30 pm (2030 GMT) on Thursday.

US Senator Mark Warner, a Democrat representing Virginia, said moves by Facebook, Twitter and YouTube to address Trump's "sustained misuse of their platforms to sow discord and violence" had come too late.

"These platforms have served as core organizing infrastructure for violent, far right groups and militia movements for several years now," said the senator, who is the incoming Chairman of the Senate Select Committee on Intelligence.

An activist group that formed a mock Facebook oversight board lamented that it took an insurrection for the social network to finally ban Trump.

"This week's coup attempt shows us that Facebook is not fit to police itself," said the group, which calls itself The Real Facebook Oversight Board, although it has no connection to the platform.

"The site remains a breeding ground for violent extremism and disinformation, its algorithm leading people into hate."

Snapchat confirmed Thursday that it locked Trump out of the photo sharing platform amid concerns over his dangerous rhetoric.

The social media announcements came after Trump's supporters stormed the US Capitol on Wednesday in an unprecedented attack that led to one woman being shot and killed by police, interrupting the normally ceremonial procedure to certify Biden's election victory.

Trump, who had addressed the mob and urged them to march on the Capitol, later released a video on social media in which he repeated the false claim of election fraud -- even telling the mob "we love you."

YouTube removed the video in line with its policy barring claims challenging election results.

Twitter said Trump's messages were violations of the platform's rules on civic integrity and that any future violations "will result in permanent suspension of the @realDonaldTrump account."

The messaging platform said Trump's account would be locked for 12 hours and that if the offending tweets were not removed, "the account will remain locked."

Critics of the online platforms argued they moved too slowly as Wednesday's violence was organized on social media, directing their ire at Zuckerberg and Twitter CEO Jack Dorsey.

"You've got blood on your hands, @jack and Zuck," tweeted Chris Sacca, an early Facebook investor who has become one of its harshest critics.

"For four years you've rationalized this terror. Inciting violent treason is not a free speech exercise. If you work at those companies, it's on you too."

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