A social media post shared by Donald Trump has become the first from Twitter to be branded 'manipulated' after it appeared to show Joe Biden endorsing the president, when in fact he was not.

Dan Scavino, assistant to the president and director of social media at the White House, shared a post Saturday, captioned: 'Sleepy Joe in St. Louis, Missouri today: "We can only re-elect @realDonaldTrump".'

But the tweet uses the line out of context of the full statement from Kansas City, Missouri, where Biden said: 'We can only reelect Donald Trump if in fact we get engaged in this circular firing squad here.'

By the time the micro-blogging site had slapped the 'manipulated content' label on it, the video had been viewed 5.2million times.

The action from the technology company came along with new rules enforced only the day before that warned users: 'You may not deceptively share synthetic or manipulated media that are likely to cause harm.