Twitter on Wednesday said it removed three of US President Donald Trump's tweets for violating its Civic Integrity policy.
It also threatened to suspend @realDonaldTrump account over violation of its community rules permanently.
Twitter had said it began limiting tweets' reach, stoking an assault of the US Capitol by a mob intent on overturning the election results.
It announced, "As a result of the unprecedented and ongoing violent situation in Washington, D.C., we have required the removal of three @realDonaldTrump Tweets that were posted earlier today for repeated and severe violations of our Civic Integrity policy.
"This means that the account of @realDonaldTrump will be locked for 12 hours following the removal of these Tweets. If the Tweets are not removed, the account will remain locked.
"Future violations of the Twitter Rules, including our Civic Integrity or Violent Threats policies, will result in permanent suspension of the @realDonaldTrump account."
Trump's supporters had stormed the Capitol in Washington during a joint session of Congress held to certify Biden's win, a desperate last-minute bid to overturn the November election that sparked chaos and accusations of a "coup" attempt.
The violence, hours after an extraordinary rally by Trump challenging his defeat, saw flag-waving backers break down barricades outside the Capitol and swarm inside, sending the legislative sessions into an emergency recess.
Extraordinary images showed security personnel barricading the chamber while lawmakers huddled inside wearing gas masks.
A woman shot in the ensuing melee was pronounced dead.