Facebook has 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 a one-day ban imposed on Trump's accounts on Facebook and Instagram was extended because of Trump's "use of our platform to incite violent insurrection against a democratically elected government."

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 President-elect Joe 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 and threatened a permanent suspension of his account if he continued breaking its rules.

The president returned to Twitter late Thursday, posting a video message that seemed aimed at calming tensions after the mahem caused by his supporters, although Trump did not go so far as to congratulate or even say the name of his successor, Biden.

"To those who engaged in the acts of violence and destruction, you do not represent our country," Trump said.

Twitter said 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.

Meanwhile, Amazon-owned gamer-centric platform Twitch disabled new video streams on a Trump account, while video-sharing sensation TikTok barred clips of Trump inciting supporters at the rally, according to media reports.

- 'Monstrous behavior' -
"Now is the time for Silicon Valley companies to stop enabling this monstrous behavior -- and go even further than they have already by permanently banning this man from their platforms," former first lady Michelle Obama said in a statement released on Twitter.

She called on social media to put in place "policies to prevent their technology from being used by the nation's leaders to fuel insurrection."

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 suspension -
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 false claims of election fraud -- even telling the mob "we love you."

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

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.

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."