One of Donald Trump’s tweets has been given a fact-check label by Twitter for the first time.
The social media giant added the warning phrase to a post from US President calling mail-in ballots "fraudulent" and predicted that "mail boxes will be robbed.”
The warning label was shared under Twitter’s new policy on misleading information.
Mr Trump wrote on Tuesday: "There is NO WAY (ZERO!) that Mail-In Ballots will be anything less than substantially fraudulent.”
Under the tweet, there is now a link reading "Get the facts about mail-in ballots" that guides users to a Twitter "moments" page with fact checks and news stories about Mr Trump's unsubstantiated claims.
The social media firm said the message may "contain potentially misleading information about voting processes".
The company updated its policies on warning labels earlier this month.
Responding to the warning post, Mr Trump again took to social media. He wrote: "Twitter is completely stifling FREE SPEECH, and I, as President, will not allow it to happen!"
The move comes after years in which Twitter has declined to apply its community guidelines and other rules of the road to the 45th US president.
It is too soon to tell whether this action represents a turning point for Twitter in its treatment of Mr Trump. But the warning labels suggest that the president has finally crossed a line that the company was not willing to move for him.
