For the first time, Twitter has flagged some of U.S. President Donald Trump's tweets with a fact-check warning. Twitter added a warning phrase to two tweets from Trump that called mail-in ballots "fraudulent" and predicted that "mail boxes will be robbed," among other things.

Trump hit out at Twitter soon afterwards, accusing Twitter of "completely stifling FREE SPEECH," warning that "I, as President, will not allow it to happen!"