Britain First is a far-right, anti-immigrant political party in the U.K. The fringe group is known for spreading hoaxes about Islam, conducting aggressive “mosque invasions” of Muslim worship spaces and campaigning for an outright ban on Islam in their country.

Trump retweeted a series of three overtly Islamophobic videos posted by Britain First’s deputy leader, Jayda Fransen. The videos purported to show Muslims committing violent and anti-Christian acts. One is called “Muslim migrant beats up Dutch boy on crutches,” another is called “Muslim destroys a statue of Virgin Mary” and the third is called “Islamist mob pushes teenage boy off roof and beats him to death!”

The legitimacy of the videos hasn’t been verified, but the Embassy of the Netherlands in the United States has already offered a correction regarding the first one. That clip originally appeared online months ago, and at the time, it was reported that the attacker didn’t appear to be a Muslim or an immigrant. On Wednesday, the embassy confirmed in a tweet that the attacker was born and raised in the Netherlands, and that he has already received and completed a sentence under Dutch law.

The second video was reportedly taken in Syria in 2013 and shows a man belonging to the al Qaeda affiliate al-Nusra. The third video reportedly shows a mob of Muslim Brotherhood supporters in Egypt throwing teens from a rooftop in 2013. It was apparently taken during the political unrest that followed the ouster of President Mohammed Morsi.

Spreading misinformation about Muslims, and conflating political extremism with Islam’s spiritual tenets, is Britain First’s bread and butter ― and the fact that Trump is amplifying one of the group’s leaders has raised concerns on both sides of the pond.

DANIEL LEAL-OLIVAS via Getty Images Jayda Fransen, deputy leader of the far-right organization Britain First, participates in a march in central London on April 1, 2017.

U.K. Prime Minister Theresa May condemned Trump through a spokesman on Wednesday, saying 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 tension,” the 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.”

Britain First is a registered political party in the U.K. that formed in 2011 as an offshoot of the far-right and now-defunct British National Party.

The group is led by co-founder Paul Golding, a longtime figure in Britain’s far-right movement, and by Fransen, who was elected to her current post in 2014.

Britain First describes itself as a “patriotic resistance and ‘frontline’” for the U.K.’s “long suffering people.” Their motto, “Take our country back,” hints at their radical goals ― to severely restrict immigration, promote Christianity above other religions in the U.K., and pull Britain away from the United Nations and other international groups.

The group claims Islam is threatening the U.K.’s Christian heritage. Their policies call for a comprehensive ban on Islam in the country ― which would mean jailing or deporting anyone “promoting the ideology of Islam,” shutting down mosques, banning the Quran and prohibiting Islamic headscarves.

Britain First has been unsuccessful in electoral politics. Golding campaigned to become London’s mayor in 2016, but only earned about 1.2 percent of the vote.

Nick Ansell - PA Images via Getty Images Paul Golding is a founder of Britain First, while Fransen is its deputy leader.

Britain First has used social media to get its message out to Islamophobes in the U.K. and abroad. The group boasts a Facebook following of nearly 2 million fans. In contrast, Britain’s Labour Party has about 1 million, while its Conservative Party has about 650,000.

In January 2016, Golding and Fransen staged what they called a “Christian patrol” with a group of about 20 Britain First members in the town of Luton. Carrying white wooden crosses, they filmed themselves handing out leaflets and intimidating local Muslim residents.

As a result, Golding and Fransen were banned for three years from entering mosques throughout England and Wales. Golding defied the court order nine days after it was handed down, the BBC reports. He was sentenced to eight weeks in prison.

Tony Margiocchi/Barcroft Media via Getty Images Golding, left, and Fransen, center, join a British First protest march at Bury Park on June 27, 2015, in Luton, England.

Fransen also faced repercussions from the Luton march. In November 2016, she was convicted of religiously aggravated harassment after verbally abusing a Muslim woman who was wearing a hijab.

The convictions don’t seem to have hindered Golding and Fransen’s campaign for Britain First. Both were charged with religious harassment this September, and on Nov. 18, Fransen was arrested in London for having used “threatening, abusive or insulting words or behaviour” at a far-right rally in Northern Ireland over the summer. She’s due in court on Dec. 14.

In June 2016, Labour politician Jo Cox was shot dead by a Nazi sympathizer who reportedly shouted “Britain First” during the attack. Fransen attempted to distance her group from the assassination, telling Reuters it had nothing to do with Britain First.

Jo Cox’s widower, Brendan Cox, criticized Trump via Twitter on Wednesday for promoting Britain First.

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 (@MrBrendanCox) November 29, 2017

Fransen, meanwhile, expressed elation over Trump’s attention.

“GOD BLESS YOU TRUMP! GOD BLESS AMERICA!” she wrote on Twitter. She later posted a video message saying she was “delighted” the president “took the time out to retweet three of my videos.”

Tell Mama, an organization that tracks Islamophobia in the U.K., has expressed serious concern over Trump’s decision to retweet Fransen.

Fiyaz Mughal, Tell Mama’s founder and director of the group Faith Matters, told the BBC that the president’s actions have “re-energised far right groups by simply pressing three clicks of a button.”

“They have effectively felt that their work is bleeding into the White House and so there is serious damage over what has happened today and there will be repercussions felt sadly over the next few months,” Mughal said. “And for those Muslims who think there is a clash of civilisations taking place it confirms their warped view. So what the President has done today is to actually strengthen the hand of extremists.”

This article has been updated to include information from the Embassy of the Netherlands in the U.S.