Tyson Fury and Deontay Wilder have been banned from facing off at their weigh-in on Saturday (NZ time), after shoving each other at the media conference before their heavyweight rematch.
The Nevada State Athletic Commission (NASC) confirmed to ESPN that the pair would be kept apart to prevent a repeat of Thursday's fiery encounter.
Brit Fury and American Wilder went nose to nose, and security rushed on stage to separate the rivals, delaying the press conference for several minutes.
The fighters also engaged in a war of words, with Fury claiming to have raised Wilder's profile and stock, and the American taunting his opponent about his mental health issues.
Top Rank president Todd duBoef - Fury's co-promoter - was surprised by the commission's decision.
"In my 25 years in boxing, I've never heard of an administrative body stepping in and prohibiting a face-off," deBoef told ESPN.
"It's the pinnacle moment before the fight - I am just shocked. That's the money shot and not having that is frustrating."
But NSAC executive director Bob Bennett said it was the right decision for the safety of both fighters and the public.
"The reason the decision was made, on behalf of the commission, is because the press conference spoke for itself," Bennett told ESPN.
"The actions of the two fighters pushing each other, which was not staged, is not indicative of the image of our sport as a major league sport, thus having a face-off is not in the best interest in the health and safety of the fighters, the public and the event.
"Quite frankly, that image, where you have two professional athletes pushing each other, where somebody could get hurt, is not keeping with the image of a major league sport and we're a major league sport.
"I'm not going to put the public or the fighters or the event in harm's way, because everybody is looking forward to a spectacular event. This decision is in the best interest of the fighters, the fans and the event."
Former WBO, WBA and IBF champion Fury (29-0-1, 20 KOs) will try to take the WBC heavyweight belt from American Wilder (42-0-1, 41 KOs) in a rematch of their December 2018 battle, which ended in a controversial draw.
The bout is scheduled for the MGM Grand Garden Arena in Las Vegas.
Join us for live updates of Wilder v Fury II from 3pm Sunday.