Donald Trump has told Theresa May "don't focus on me" after Downing Street said it was wrong for the president to share anti-Muslim videos posted online by the deputy leader of Britain First.
The US president said the British Prime Minister should instead "focus on the destructive radical Islamic terrorism that is taking place within the United Kingdom".
It comes after Mr Trump caused outrage after retweeting three posts by the group's deputy leader Jayda Fransen to his 43.6 million followers, including footage from the Netherlands purporting to show a Muslim migrant committing crimes.
The Prime Minister's official spokesman said Britain First was dedicated to causing division among communities and that the president had been "wrong" to share the posts.
He originally addressed the tweet to @theresamay, who has just six followers, rather than the Prime Minister's account.
He later re-sent the tweet to tag the Prime Minister's correct Twitter handle, saying: @Theresa_May, don't focus on me, focus on the destructive Radical Islamic Terrorism that is taking place within the United Kingdom. We are doing just fine!
.@Theresa_May, don’t focus on me, focus on the destructive Radical Islamic Terrorism that is taking place within the United Kingdom. We are doing just fine!— Donald J. Trump (@realDonaldTrump) November 30, 2017
Commenting on Mr Trump's post, Fransen, 31, who was convicted last November of religiously aggravated harassment for hurling abuse at a Muslim woman in a hijab, said: "Well said Mr President!"
Earlier Downing Street made clear the Government's dismay at the way he had publicised the views of a such far-right group.
"Britain First seeks to divide communities through their use of hateful narratives which peddle lies and stoke tensions," the Prime Minister's official spokesman said.
"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.
"It is wrong for the president to have done this."
Meanwhile, Conservative MP Nadhim Zahawi shared a letter he has written to Mr Trump to register his "strong discontent" at the retweets.
Referencing Mr Trump's planned state visit to the UK, Mr Zahawi said: "You are soon due to visit the United Kingdom. When you are here, I believe you would find enlightening the experience of visiting our beautiful cities like Coventry, Birmingham, Manchester and London."
He added: "They are so far removed from the stereotypes that the videos of Britain First try to portray."
The UK's Communities Secretary Sajid Javid also condemned Mr Trump for endorsing the views of the far-right group, which he said "hates me and people like me".
He tweeted: "So POTUS has endorsed the views of a vile, hate-filled racist organisation that hates me and people like me. He is wrong and I refuse to let it go and say nothing."
So POTUS has endorsed the views of a vile, hate-filled racist organisation that hates me and people like me. He is wrong and I refuse to let it go and say nothing— Sajid Javid (@sajidjavid) November 29, 2017
British Foreign Secretary Boris Johnson described the group as "divisive" and "hateful" but stopped short of criticising the president for sharing the posts.
He said on Twitter: "Britain First is a divisive, hateful group whose views are not in line with our values. UK has a proud history as an open, tolerant society and hate speech has no place here."
British Foreign Office minister Alistair Burt described the retweets as "both alarming and despairing", saying: " As Minister for the Middle East, proud of our relationships with the Islamic world and those within it, the White House tweets are both alarming and despairing tonight. This is so not where the world needs to go."
The posts included unverified videos titled "Muslim migrant beats up Dutch boy on crutches!" and "Muslim Destroys a Statue of Virgin Mary!"
The Dutch embassy in the US said the perpetrator of the violent act in one of the videos was born and raised in the Netherlands.
White House spokeswoman Sarah Huckabee Sanders said the president had been seeking to "promote strong borders and strong national security".
The Prime Minister is currently on a tour of the Middle East.
Hours before Mr Trump's latest tweet, the Prime Minister's spokesman made clear the invitation for the president to make a state visit, made when Theresa May met Mr Trump in Washington in January, still stood.