Evander Holyfield has accused Mike Tyson of turning down $25million to fight him for a third time.
Holyfield, 58, claims he made the offer with a view to the trilogy fight taking place on May 29 at the Hard Rock Stadium in Miami.
But he looks set to walk away from the negotiations after growing increasingly frustrated with the fellow undisputed heavyweight world champion.
The former cruiserweight and heavyweight’s manager Kris Lawrence said: “Team Holyfield sincerely believed a deal was imminent … and there were multiple other offers conveyed to Team Tyson.
“However, Team Tyson’s demands recently became untenable, and not what Mike Tyson had originally agreed on in direct conversations with Holyfield.”
Holyfield added that he believed a deal was close after several months of negotiating but that Tyson, 54, changed his demands.
The rivals last met in 1997 when Tyson bit Holyfield’s ear and was disqualified and later banned from boxing.
Holyfield had won their first meeting a year earlier with a stoppage in the 11th round in a fight delayed by six years following Tyson’s defeat by Buster Douglas and his subsequent prison term.
Holyfield’s claim follows a statement from Tyson which said he would no longer be working with the Triller pay-per-view service which screen his comeback fight with Roy Jones Jr last year.
The company was planning to host Tyson’s next fight on the same card as lightweight world champion Teofimo Lopez’s mandatory title defence against George Kambosos.
But Tyson said: “Just to be clear, there is no Tyson with Triller fight. I don’t know any Triller executives personally. I don’t have a deal with Triller or any head executive representing them for the next event.
“I’m a partner in Legends Only League, and my next event is with my league. I will never do another event or any business with Triller, so anyone misrepresenting that they own the rights to my name or my next event isn’t true. I am not with or ever will be with Triller’s Fight Club.”