Donald Trump has been accused of "spreading hate" after he retweeted unverified anti-Muslim videos from a fringe far-right UK political leader.
In a particularly outrageous morning on Twitter, the US President also implied that one of his fiercest critics, cable news host Joe Scarborough, may have been involved in the death of a co-worker.
The anti-Muslim videos were tweeted without explanation in the early hours of Wednesday morning from the President's personal Twitter account to his nearly 44 million followers.
Britain First is a UK-based far-right political party that is vehemently anti-immigration.
Current campaigns include to ban the BBC from "discriminating against white Britons", to stop the expansion of mosques and the "persecution" of leaders Paul Golding and Jayda Fransen. Fransen was arrested and questioned days ago over a speech made in Northern Ireland this year.
The videos are virtually impossible to verify but appear anti-Islamic in nature. One contains the caption "Muslim migrant beats up Dutch boy on crutches" and shows two boys standing in a park. One places his arm around the other before punching him and kicking him on the ground.
The second shows a picture of a man in Muslim dress holding a statue of the Virgin Mary and contains the caption "Muslim Destroys a Statue of Virgin Mary!"
Another video is labelled "Islamist mob pushes teenage boy off roof and beats him to death!" It reveals a group of young men - one wearing an Islamic State flag - on a rooftop in an undisclosed location. A young man is thrown by the others off a part of the roof.
The tweets were followed four hours later by another message from the President retweeting White House press secretary Sarah Sanders who said "Christmas comes early! Finally, good news from @CNN" in response to news that CNN staff would boycott the White House Christmas party.
It's unclear whether Trump himself retweeted the tweets, but Fransen revelled in the attention, saying "God bless you Trump". She also retweeted several articles noting the President's actions.
Other videos in Fransen's Twitter feed show her walking the streets of Luton with a Christian cross. One video is called "Muslims attack an Englishman in London!" and another has the headline "Crowds gather for public execution of woman accused of adultery!"
Britain First is a fringe party with no elected officials, however it has a strong social media footprint and wants to crackdown completely on immigration. It also wants to offer cash to foreigners to leave the UK and make it "treason" to increase immigration quotas.
Leader Paul Golding was recently jailed for eight weeks after breaking a High Court ban on entering mosques after the group filmed themselves in "mosque invasions" to confront worshippers.
Condemnation from leading figures in the UK was swift.
Via a spokesman, Prime Minister Theresa May said it was "wrong for the President to have done this".
"Britain First seeks to divide communities through their use of hateful narratives which peddle lies and stoke tensions," the Downing St spokesman told the Evening Standard.
"They cause anxiety to law-abiding people. British people overwhelmingly reject the prejudiced rhetoric of the far-right, which is the antithesis of the values that this country represents — decency, tolerance and respect."
Broadcaster Piers Morgan said: "Good morning, Mr President @realDonaldTrump — what the hell are you doing retweeting a bunch of unverified videos by Britain First, a bunch of disgustingly racist far-right extremists?
"Please STOP this madness & undo your retweets."
Labour MP David Lammy said: "Trump sharing Britain First. Let that sink in. The President of the United States is promoting a fascist, racist, extremist hate group whose leaders have been arrested and convicted. He is no ally or friend of ours. @realDonaldTrump you are not welcome in my country and my city."
"Do not forget that the man who murdered Jo Cox shouted "Britain First". Trump has gone beyond the pale today."
Brendan Cox, the widowed husband of former UK Labour MP Jo Cox, who was killed in the run-up to the Brexit referendum, said: "Trump has legitimised the far right in his own country, now he's trying to do it in ours.
"Spreading hatred has consequences and the President should be ashamed of himself."
It comes as Trump vowed to end the "war on Christmas" after the Obamas favoured a more non-denominational approach.
This year, Trump's first presidential Christmas Card will say "Merry Christmas and a Happy New Year" rather than the generic "happy holidays", which has become popular in recent years but also railed against as being overly politically correct.
Trump implies critic was involved in death
Trump has suggested MSNBC host Joe Scarborough may have had something to do with the death of an intern in 2001.
Soon after his anti-Muslim push, Trump was back on Twitter weighing into the scandal surrounding Matt Lauer. The US Today show host was sacked Wednesday morning over "sexual misconduct" allegations.
Trump quickly turned the discussion to Today's network, NBC, saying its executives should also be fired for "putting out so much fake news".
He went on to make an extraordinary implication about one of his fiercest critics, MSNBC's Morning Joe host Joe Scarborough.
The "unsolved mystery" Trump is referring to is the death of Lori Klausutis, 28, an intern who was found dead in Scarborough's Florida office in 2001 when he was still a Republican congressman.
To be clear, there is no mystery in her death.
The medical examiner concluded that Klausutis "lost consciousness because of an abnormal heart rhythm and fell, hitting her head on a desk".
"The head injury caused the death," he said a month after she was found.
There is no evidence of foul play, but the tragedy has been spun into a conspiracy theory, which has now been repeated by the President of the United States.
Trump's comment was swiftly condemned.
Scarborough dismissed the allegation by saying Trump "is not well".
Trump used to be close to Scarborough and his co-host and partner Mika Brezinski, but they have had a massive falling out since he won the presidency.
He famously mocked Brzezinski's intelligence, calling her "dumb as a rock", and claimed that she had been "bleeding badly from a face-lift" in a nasty Twitter blast in June.