President Donald Trumpretweeted a racist clip of Fox News Host Tucker Carlson, who’s facing backlash for claiming the notion of a white supremacy problem in the U.S. is “a hoax” created by the left and the media.

The video ― created by The Daily Caller, a conservative news site that Carlson co-founded ― features the Fox host discussing and questioning the legitimacy of Rep. Ilhan Omar’s (D-Minn.) prior marriage, immigration status and name. Omar, an American citizen, was born in Somalia and immigrated to the U.S. as a child.

The “sham marriage” that Carlson refers to is a popular right-wing conspiracy theory that Omar married her brother in order to bypass U.S. immigration laws. There is no evidence that indicates this is the case, and the theory originated from an anonymous internet forum post in 2016.

Omar has denied the claim and provided a timeline of her marital history. In 2018, she showed a reporter from the Minneapolis Star Tribune images of her father’s immigration documents, which did not list her former husband among his children.

But this is not the first time that the president has drawn attention to the unsubstantiated theory.

“Well, there is a lot of talk about the fact that she was married to her brother,” Trump told reporters last month, before adding: “I know nothing about it.”

Trump has a history of engaging in or promoting racist attacks that question the legitimacy of the congresswoman’s status as an American. He has claimed that Omar hates America and said that she, alongside three other progressive Democratic congresswomen, should “go back and help fix the totally broken and crime infested places from which they came.”

Carlson currently faces public backlash for claiming that white supremacy is not a threat in America just days after a shooter killed 22 people and injured dozens more at a Walmart in El Paso, Texas. The shooter reportedly penned a racist, anti-immigrant manifesto before driving nine hours to the largely Hispanic border town.

“This is a hoax, just like the Russia hoax,” Carlson said on Tuesday of the notion that white supremacy was a major threat in the U.S. “It’s a conspiracy theory used to divide the country and keep a hold on power. That’s exactly what’s going on.”

Fox News and Carlson have lost several advertisers, including Long John Silver’s, Nestlé and HelloFresh, in the aftermath of his claim.

When the president was asked on Wednesday if he was concerned about the rising threat of white supremacy, he told reporters he was concerned about all hate groups, “whether it’s white supremacy, whether it’s any other kind of supremacy.”