YouTube said it would start removing content that falsely alleges widespread voter fraud changed the result of the US election.
The update applies to all new content, including videos from President Donald Trump.The company had previously labelled potentially misleading election videos, adding links to accurate information.
YouTube said “enough states have certified their election results to determine a president-elect.”
Democrats have criticized YouTube for not doing enough to take down fake news and conspiracy theories on the platform.
Mr. Trump and senior Republicans have repeatedly made unsubstantiated claims that the election was “rigged.”
Trump’s lawyers have failed to provide evidence of this.
The announcement comes after a “safe harbour” deadline – which sets a date by which states need to certify the results of the presidential election. It also said that the move was in line with its historical approach to US presidential elections.