(CNN) -- Mixed martial arts organization UFC has suspended fighter Matt Mitrione indefinitely for comments made in an interview Monday night about transgender MMA fighter Fallon Fox.
Born a man, Fox became a woman through surgery and then trained to fight in mixed martial arts, a story that she revealed earlier to Sports Illustrated.
One of Fox's recent female competitors criticized her for not disclosing that she had had a sex change operation before fighting. Fox, who disclosed the operation after the match, won.
Mitrione, a former NFL player, appeared Monday on a show called "The MMA Hour."
He said: "I have not seen a man beat a woman like that since Chris Brown beat Rihanna."
"That is a lying, sick, sociopathic, disgusting freak," Mitrione said. "And I mean that. Because you lied on your license to beat up women. That's disgusting. You should be embarrassed yourself."
Fox is the first MMA competitor to go on record about being transgender.
"The reaction has been positive," the 37-year-old said in a March CNN story. "It's just some people, some of society doesn't get it yet. And this is what we're trying to do now, is to inform people and let them know about transgender athletes."
UFC, or Ultimate Fighting Championship, a mixed martial arts promotion group, released a statement about Mitrione's comments.
"The UFC was appalled by the transphobic comments made by heavyweight Matt Mitrione today (Monday) in an interview on the 'MMA Hour,' " the release said. "The organization finds Mr. Mitrione's comments offensive and wholly unacceptable and -- as a direct result of this significant breach of the UFC's code of conduct -- Mr. Mitrione's UFC contract has been suspended and the incident is being investigated.
"The UFC is a friend and ally of the LGBT community, and expects and requires all 450 of its athletes to treat others with dignity and respect."
CNN's Justin Lear contributed to this report.