The language app Babbel has apologised for airing an advertisement during Tucker Carlson Tonight, calling the Fox News show "repugnant".

Mr Carlson's show, which is known for presenting white nationalist ideas, has lost a number of advertisers in the last few months. Many companies have been highlighted for their support of the show by non-profit media watchdogs like Sleeping Giants, which Babbel tagged in a response to their Tuesday afternoon tweet apologising for their ad.

"If you saw our ad on Tucker Carlson’s show, you’re right to be upset. We are too," the company's tweet read. "While we did place our ad with Fox, we did not know it would air on a show so repugnant and at odds with our mission and values. We are blacklisting the show going forward. We are deeply sorry."

Babbel's ad aired during an episode of the show earlier this week.

In response to their apology, a spokesperson for Fox News told the Hill the company would "not allow voices like Tucker Carlson’s to be censored by agenda-driven intimidation efforts from the intolerant partisan activists Media Matters, Sleeping Giants and Moveon.org whose only goal is to silence conservative thought they don’t agree with."

Mr Carlson came under fire in December for airing a segment in which he suggested immigration made the US made the country "poorer and dirtier and more divided." He has been steadily losing advertisers ever since.