LONDON (REUTERS, AFP) - United States President Donald Trump said he would apologise for sharing anti-Muslim videos originally posted by a leader of a far-right fringe group in Britain and had not intended to cause offence.

Speaking to ITV's Good Morning Britain show, Trump said he knew nothing about the group but that he was the "least racist person that anybody's going to meet" and that his retweet was not an endorsement.

Trump sparked outrage in Britain in November when he retweeted, in quick succession, three anti-Muslim videos posted by Jayda Fransen, the deputy leader of Britain First who was in 2016 convicted of religiously aggravated harassment of a Muslim woman.

The show's host Piers Morgan accused the President of causing "huge anxiety and anger in my country, because Britain First is basically a bunch of racists, fascists".

"Of course I didn't know that," Trump responded in excerpts of the interview.

When pressed on whether he would apologise for his retweet, Trump said that if the group was made up of racists then he would.

"Here's what's fair, if you're telling me they're horrible people, horrible racist people I would certainly apologise if you would like me to do that," Trump said.

"I know nothing about them. I don't want to be involved with people, but you're telling me about these people because I know nothing about these people."

"Perhaps it was a big story in the UK, but in the United States it wasn't a big story," he said.

"I did a retweet. When you do those retweets they can cause problems because you never know who's doing it to start off with," the President told Morgan.

Trump said he did not mean to cause any difficulty for Britain, a country he said he loved very much.

"I can tell you I have a very good relationship with your Prime Minister," Trump said. "She's been doing a very good job. We actually have a very good relationship, although a lot of people think we don't."

"I support her, I support a lot of what she does and a lot of what she says and I support you militarily very much. We will come to your defence if anything should happen, which hopefully will never happen. I am a tremendous supporter of the UK."