The latest round of negotiations for the potential megafight between welterweight champions Manny Pacquiao and Floyd Mayweather Jr. are over before they have even begun.

Leonard Ellerbe, one of Mayweather's advisors, and Golden Boy Promotions CEO Richard Schaefer both told ESPN.com Monday that they were notified that Pacquiao promoter Bob Arum of Top Rank was not interested in coming to the table.

"We have been informed that Bob Arum is not interested in pursuing a fight between Mayweather and Pacquiao at this time," Schaefer said.

Mayweather knocked out Victor Ortiz in his return to the ring after 16 months off in September, and Pacquiao eked out a controversial majority decision against rival Juan Manuel Marquez in their third meeting Saturday night at the MGM Grand in Las Vegas.

That set the table for the showdown that looms as the biggest money fight in boxing history, especially with Mayweather announcing two weeks ago that he planned to return May 5 at the MGM Grand and, according to Ellerbe, wanted to "make the biggest fight possible and everyone knows what that fight is, the little fella (Pacquiao)."

However, that does not appear to be the plan Arum and Pacquiao have, even if they had said they were open to it before the Marquez fight.

Schaefer said the notification came in an email from retired federal judge Daniel Weinstein, the mediator who has worked closely with the sides to settle numerous lawsuits and issues in recent years.

"I am sick and tired of Bob Arum twisting the truth. It's another case of 'yesterday I was lying, today I'm telling the truth,' " Schaefer said, invoking Arum's most famous quote. "The truth of the matter is that we received this afternoon an email from retired federal judge Daniel Weinstein, who has informed us that Top Rank is pursuing a rematch with Marquez and, therefore, is not interested in immediate talks for a possible Mayweather-Pacquiao fight. This is obviously as clear as it can be that they have no intentions of making a Mayweather-Pacquiao fight. Therefore, Floyd Mayweather will have no other choice than to move on and identify and lock in another opponent for his ring return on May 5."