Facebook boss Mark Zuckerberg has waded into a fact-checking row between President Trump and rival social network Twitter.
Mr Zuckerberg said in an interview that his influential platform, which reportedly has 2.5 billion global users, “shouldn’t be the arbiter of truth” in fact-checking everything people say online.
It came as Twitter marked one of the president's tweets - making unsubstantiated claims about widespread fraud in absentee postal voting, known as mail-in ballots in the US - as misleading for the first time.
His since-deleted post repeating his often made "rigged election" allegations was tagged with an alert message telling other users to “Get the facts about mail-in ballots”.
Studies have not shown widespread evidence of this, with CNN reporting that one law professor found just 31 instances of such fraud between 2000 and 2014.
Postal voting is expected to increase dramatically in the November presidential elections, with Trump seeking a second term, due to concerns about in-person voting amid the coronavirus pandemic.
But Mr Zuckerberg has criticised Twitter after its new labelling system flagged the presidential's tweet on the subject.
He told Fox News: "We have a different policy, I think, than Twitter on this.
"I just believe strongly that Facebook shouldn't be the arbiter of truth of everything that people say online.
Mr Zuckerberg added: “In general, private companies probably shouldn't be, especially these platform companies, shouldn't be in the position of doing that.”
Facebook also funds a fact-checking programme, but when Mr Trump posted the same comments there about postal votes it was not labelled or removed.
The social network said the post had not broken its rules due to its belief that “people should be able to have a robust debate about the electoral process”.
It came as President Trump, a prolific Twitter user with more than 80 million followers, prepared to sign an executive order - which gives him direct powers to enforce laws - on social media .
In the early hours today, he again tweeted accusations that “Big Tech” was trying to “censor” ahead of the election.
The president has previously threatened to shut down social platforms online that he accused of choking conservative opinion.
No further details on the executive order were given by White House officials and there is uncertainty over what legal powers he has to create such regulation without the approval of Congress.
