US President Donald Trump has said he is prepared to apologise for retweeting posts from a British far-right group.
In an interview with ITV's Piers Morgan, Mr Trump said he knew "nothing" about Britain First before sharing three of its videos in November.
"If you are telling me they're horrible people, horrible, racist people, I would certainly apologise if you'd like me to do that," he told Morgan.
The interview, held in Davos, will be broadcast on 28 January at 22:00 GMT.
The president's sharing of the controversial videos to his 40 million followers sparked a Twitter row with the UK prime minister, who criticised the move.
"I'm very clear that retweeting from Britain First was the wrong thing to do," Mrs May said, prompting Mr Trump to instruct the PM to focus on "terrorism" in the UK instead.
'Good relationship'
Asked if he regretted the tweets, Mr Trump said, "it was done because I am a big believer in fighting radical Islamic terror".
But he insisted he knew "nothing about" Britain First before sharing posts by the group's deputy leader Jayda Fransen - who is facing a trial in April, accused of using threatening, abusive or insulting words at a protest in Belfast last year.
"I know nothing about them, I don't want to be involved with people [like that]," Mr Trump told Morgan.
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One of the videos retweeted by Mr Trump shows unverified footage of a "Muslim migrant" attacking a young Dutch man on crutches, with another showing a man smashing a statue of the Virgin Mary.
The third video, originating from riots that took place in Egypt in 2013, shows a man being pushed from the top of a building.
Mr Trump told Morgan: "Here's what's fair - if you're telling me they're horrible people, horrible racist people, I would certainly apologise if you'd like me to do that."
He also said the controversy was not a big story in the US.
Media captionMay: We're not afraid to say when US has got it wrong
Britain First, which was set up in 2011 by former members of the far-right British National Party (BNP), uses social media to gain attention for what it calls the "Islamification of the UK".
Responding to Mr Trump's interview, Ms Fransen said she believed he had been "railroaded" into offering to apologise.
She said: "The fact is Donald Trump retweeted those because they are a matter of national and worldwide security.
"Islamic terrorism is affecting us all and he's been railroaded into saying he would offer an apology."
Ms Fransen said if she was really a "horrible, nasty racist" the US president "would condemn me".
But she added: "It's not true."
'Significant climbdown'
Speaking to ITV after the interview, Morgan said it was "right and proper" that Mr Trump should apologise, adding: "I think this is a significant climbdown by the president".
The pair have been amiable since Morgan, who has described the president as a "good friend", won the US reality show Celebrity Apprentice in 2008 - which was judged by Mr Trump.
Brendan Cox, whose wife Jo Cox was murdered by an extremist who shouted "Britain First" as he fired his gun, praised Morgan for pushing for an apology.
"Not many have succeeded in getting one," said Mr Cox, who was among those who rebuked Mr Trump for promoting the far-right group.
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During the interview, on the sidelines of the World Economic Forum, Mr Trump also told Morgan that he did not want to "cause any difficulty for your country".
He spoke of his "love" for the UK and for Scotland in particular, which he described as a "very special place", despite cancelling a planned visit to the UK in February.
Asked about whether some people were opposed to a UK visit, Mr Trump said: "I hadn't heard about banning, I think a lot of the people in your country like what I stand for, [including] tough borders."
Mr Trump added that he had a "very good relationship" with the UK prime minister, who he met in Davos shortly before the interview on Thursday.
"A lot of people think we don't," he said.
In an earlier exchange with the PM in Davos, Switzerland, President Trump told Mrs May: "We love your country."
He also said the US and UK were "joined at the hip" on military matters, while Mrs May said they stood "shoulder to shoulder" in facing shared threats.