For the first time, Twitter and Facebook removed the accounts of Donald Trump, eventually escalating their crackdown on the social media messages of the president after he encouraged and assisted rioters at the US Capitol.

Following "repeated and serious" violations of its rules on election disinformation, Twitter forced Mr. Trump to delete those messages, including a video sending love to the violent rebellion in Washington protesting his defeat to Joe Biden in November.

Google's YouTube also deleted the same video and helped tip the scales on Facebook, which said Mr. Trump's page was barred from posting for 24 hours.

"We have required the removal of three @realDonaldTrump Tweets that were posted earlier today for repeated and severe violations of our Civic Integrity policy as a result of the unprecedented and ongoing violent situation in Washington, DC," Twitter wrote in a statement on its website.

Once the tweets are removed, after a 12-hour lock is released, Mr. Trump can get his account back.

Social media, particularly Twitter, has been the preferred way for Mr. Trump to disseminate information directly to the public for years. Mr. Trump has posted daily since November without proof that the presidential election was "rigged." Twitter has branded hundreds of Mr. Trump's posts as controversial or deceptive, and Facebook has flagged misleading election posts by pointing users to reputable news sources, but Wednesday was the first time that either platform was even briefly kicked off by the president. Twitter has threatened to absolutely block Mr. Trump if he tries to violate the rules.

"The firm tweeted from its @TwitterSafety handle, "Future breaches of the Twitter Laws, including our Civic Integrity or Violent Threats policies, would result in permanent suspension of the @realDonaldTrump account.

The video that Mr. Trump was asked to delete on Twitter showed the president speaking at the US Capitol to rioters. Mr. Trump ordered them to "go home," but the election outcome was also deemed "fraudulent."

Most of the Twitter messages from Mr. Trump appear simultaneously on Facebook, where they are widely circulated by sharing and commenting among followers. Recently, the company began to mark deceptive Trump posts with links to more context, such as information about Mr. Biden's election victory but generally allowed users to continue sharing and responding to his posts until the temporary ban on Wednesday.

Facebook, the largest social network in the world, said it was horrified by the protests and removed all praise for the Capitol rebellion, calls to carry arms to some places around the US, and videos and images of demonstrators in the Capitol. "They represent the promotion of criminal activity that violates our policies at this stage," the company said in a blog post. The Instagram photo-sharing service on Facebook also said it would lock the account of Mr. Trump for 24 hours.

"These are the things and events that happen when a sacred landslide election victory is so unceremoniously & viciously stripped away from great patriots who have been treated badly & unfairly for so long," read another Trump tweet that was blocked, which emerged as the violence unfolded.

For years, Twitter has been under pressure to take a harsher stand against the account of Mr. Trump, which he also uses to spread racist attacks and disinformation. On Wednesday, calls for Twitter CEO Jack Dorsey to ban the president were widespread. In Washington, Mr. Trump's supporters had gathered for a speech in which he urged them to demand that the election be reversed.

Other guidelines have been created by Twitter in the past to restrict the spread of Mr. Trump's incendiary tweets without fully deleting them, including warning labels that mask the content of messages, arguing against their elimination on the basis of the importance of news coming from a world leader. In recent months, however, Twitter has also taken a firmer stance against Mr. Trump. Executives have said that Mr. Dorsey is not the last word for punishing elected officials, and his top policy executive, Vijaya Gadde, is responsible for that decision.

In May, Twitter first flagged a few of Mr. Trump's tweets for disinformation, setting off a more hostile response to the posts of the president in the wake of national demonstrations against racial justice sparked by the death of George Floyd. After November, hundreds of tweets by Mr. Trump have been obscured or branded for mischaracterizing the outcome of the election. Twitter started shortly after the election that Mr. Trump will not be considered a world leader when he leaves office in January and may be disciplined more harshly for his abuses.

After the company's announcement, Twitter shares dropped around 2 percent in extended trade. Facebook shares have changed nothing.