In a rare rebuke to Britain's closest ally, British Prime Minister Theresa May's spokesman has said US President Donald Trump was wrong to retweet videos posted by a leader of a British far-right group.
However, Downing St rejected calls from opposition MPs to revoke Mr Trump's invitation to pay a state visit to Britain.
Mr Trump retweeted three videos from the account of deputy Britain First leader Jayda Fransen, purporting to show violence by Muslims.
The group's tweets read: "VIDEO: Islamist mob pushes teenage boy off roof and beats him to death!", "VIDEO: Muslim Destroys a Statue of Virgin Mary!" and "VIDEO: Muslim migrant beats up Dutch boy on crutches!"
Britain First is a far-right group that opposes multiculturalism and what it calls the "Islamisation" of Britain.
It has run candidates in local and national elections — with little success — and has campaigned against the construction and expansion of mosques.
The tiny extremist group appeared delighted at the publicity boost from a leader with almost 44 million Twitter followers.
Mr Trump did not offer any explanation for why he retweeted the videos.
As a candidate, Mr Trump called for "a Muslim ban" and as President has issued executive orders banning entry from some citizens of multiple countries, although courts have partially blocked them from taking effect.
Calls for visit invitation to be revoked
In response, Labour Party MP David Lammy tweeted: "realDonaldTrump you are not welcome in my country and my city."
Another Labour MP, Chuka Umunna, said Mr Trump's invitation to visit Britain "should be withdrawn."
Mr Trump's retweets were also condemned by the husband of murdered British MP Jo Cox, who was shot and stabbed to death by a far-right supporter.
Some reports at the time said her killer shouted "Britain first" as he attacked Ms Cox. At the time the Britain First group issued a statement condemning the killing.
"Trump has legitimised the far right in his own country, now he's trying to do it in ours. Spreading hatred has consequences & the President should be ashamed of himself," Brendan Cox wrote on Twitter.
Ms May announced in January that Mr Trump had accepted an invitation for a state visit to Britain, one of the biggest honours the country can bestow on foreign leaders.
Almost a year later, no date has been set, and opponents of Mr Trump have vowed to stage large protests if he does come.
Ms May's spokesman, James Slack, said it was "wrong" for the president to have retweeted Britain First as the group sought to divide communities through its use of "hateful narratives which peddle lies and stoke tensions."
But the PM's office said the state visit would not be cancelled.
'God bless you Trump!'
Founded in 2011, Britain First has staged direct-action protests at mosques and is active on social media.
The group regularly posts inflammatory videos purporting to show violence by Muslims, without context or supporting information.
Ms Fransen quickly responded on Twitter, saying: "Donald Trump himself has retweeted these videos and has around 44 million followers! God bless you Trump!"
Ms Fransen has been charged with causing religiously aggravated harassment over leaflets and videos that were distributed during a criminal trial earlier this year.
She has separately been charged with using "threatening, abusive or insulting words or behaviour" over a speech she made in Northern Ireland in August. She is currently on bail.
She was convicted last year of religiously aggravated harassment and fined after hurling abuse at a Muslim woman wearing a hijab.