Fox News announced that they do not plan on booking Michael Knowles moving forward after he called 16-year-old climate activist Greta Thunberg "mentally ill" on the network Monday night.

Knowles, who hosts The Michael Knowles Show for the Daily Wire, appeared on Fox News for a segment about climate change and Thunberg's activism. He was accompanied on the show by Chris Hahn, a former aide to Senate Minority Leader Chuck Schumer, who took exception to Knowles' characterization of the teenager.

Fox News no longer plans to bring Knowles on the network anymore, a spokesperson for the cable news station confirmed to the Washington Examiner after it was first reported by the Hollywood Reporter.

"If it were about science it would be led by scientists rather than by politicians and a mentally ill Swedish child, who is being exploited by her parents and by the international Left," Knowles stated, sparking a visceral reaction from Hahn, who proceeded to call him "despicable" and demand he apologize.

The network called Knowles' remarks "disgraceful" and issued an apology to both their viewers and Thunberg after the segment gained attention on social media.

Thunberg has been diagnosed with ADHD and Asperger's. She has called her condition "a superpower" that allows her to address climate change more effectively.

UPDATE: Hahn told the Washington Examiner, "What Mike Knowles said last night should not be tolerated. It’s unfortunate that the debate in this country has sunk to a level where some people think it’s ok to denigrate children. We saw this during the Parkland Student Protests and we’re seeing it today with the attacks on Greta. Keep in mind that ad-hominem attacks are only used when the attacker doesn’t have a legitimate point to make in response to an issue. This needs to stop."