Earlier this week, boxing promoter Bob Arum blasted GOP front-runner Donald Trump, calling him a “clown” and saying other countries were laughing at the prospect of him as president.

At a boxing event on Friday, Arum, 84, called Trump a “disgrace,” and then challenged him to a charity boxing match. The boxing promoter also called out the other Republican candidates for not hitting back at Trump.

“Any time [Trump] wants, all proceeds go to charity. Let me take on Donald Trump,” Arum said. “I’ll handle him, not like these guys who don’t hit him and treat him with kid gloves. I mean, he’s a disgrace. You can’t say what he’s saying; you can’t make these hateful speeches when you’re running for President of the United States.”