Manny Pacquiao adviser Michael Koncz told ESPN.com on Thursday that Floyd Mayweather Jr. has declined to agree to terms for a penalty that would cost either man $5 million in the event of a failed drug test before or after their May 2 megafight at the MGM Grand in Las Vegas.

"Today we were informed that Mayweather turned down the request," Koncz said. "Manny had requested that there would be a reciprocal fine of $5 million for a failed drug test."

Koncz said that even though the agreements for the fight are signed, as is a separate agreement for the United States Anti-Doping Agency to oversee random blood and urine testing for the fight, they were still discussing terms for a substantial fine in the event of a dirty test. But Koncz said Mayweather attorney Jeremiah Reynolds sent a letter to Pacquiao attorney David Moroso on Thursday declining to enter into any agreements on a financial penalty for a failed drug test.

Manny Pacquiao's adviser says Floyd Mayweather Jr. has declined a $5 million penalty for either fighter in the event of a failed drug test before or after their May 2 megafight in Las Vegas. Al Bello/Getty Images

Leonard Ellerbe, CEO of Mayweather Promotions and Mayweather's close adviser, said Koncz should have had those terms negotiated into the main contract.

"Michael Koncz is an idiot, and Manny Pacquiao should be ashamed to have him as his representative, in my opinion," Ellerbe told ESPN.com. "It's obvious he didn't read the contract. Why would he have his fighter sign something he was not happy with? The deal was negotiated up and down by his promoter [Bob Arum of Top Rank] on behalf of Manny with Floyd and Mayweather Promotions, and it's been well documented in the media for quite some time.

"If this moron didn't convey his fighter's wishes when the negotiation was going on, that's their problem. This is a lame-ass attempt to generate publicity."

Drug testing, of course, has been front and center throughout the five-year-plus saga to get boxing's most anticipated fight signed. When the sides first negotiated the bout in late 2009 and early 2010, they had agreed to all aspects of the deal except for the drug-testing protocol. Mayweather insisted on random, Olympic-style blood and urine testing, Pacquiao declined to agree to the specific form of drug testing, and the deal fell apart.

Not long after that, Pacquiao sued Mayweather for defamation and slander for saying that he had used performance-enhancing drugs, which Pacquiao has always denied. The case was ultimately settled out of court with Mayweather paying Pacquiao an undisclosed seven-figure sum.

"They have made derogatory statements for years about Manny [supposedly using PEDs], and now we challenged them by asking for the $5 million fine, and they refused to do it. It's disheartening," Koncz said.

Mayweather has required himself and his opponents to be tested by USADA for all of his bouts since 2010, while Pacquiao has sometimes used the Voluntary Anti-Doping Association to randomly test him and his opponent in recent years.

For the May 2 welterweight unification bout, expected to be the richest fight in boxing history, Pacquiao agreed to Mayweather's demand for USADA testing, and they signed contracts with the agency about three weeks ago.

When asked why Pacquiao didn't negotiate the fine into the master fight agreement, Koncz said he was concerned with getting the fight signed and did not want to do anything to jeopardize very delicate negotiations. Besides, he said, both camps knew they would have to sign a separate agreement with USADA to outline the specific terms of the testing.

"We were still discussing the penalty. We've been going back and forth about it for the past three or four weeks. We hoped that we could sign that agreement around the same time as the agreement with USADA," Koncz said. "[The Mayweather camp] is saying, 'Why wasn't it brought up for the main contract?' Why does it have to be brought up for the main contract? Everything in the main contract pertains to the co-promotion and the promoters. You can argue all day if [a penalty agreement] should be with the USADA contract or the main contract. What do you have to lose or gain in that argument? It's a simple thing -- if you fail, you pay the other guy $5 million. The issue is simple -- are you willing to agree to a penalty of $5 million? The drug-testing terms and any penalty, that's between the fighters not the promoters.

"We have no recourse. We can't force Floyd into something. But we gave them an opportunity to put their money where their mouth is and they wouldn't. I won't speculate why. To me there is no legitimate argument. We know we're clean. That's why Manny said he would pay $5 million if he tested dirty. Manny was surprised [Mayweather refused]. He can't figure out why they wouldn't agree to it when Floyd is always talking about cleaning up the sport of boxing."

Added Ellerbe: "If Manny Pacquiao tested positive, it is going to cost him a whole lot more than $5 million. All parties signed a contract agreeing to every term. Where has this idiot Koncz been? It sounds like he didn't read the documents they signed. No wonder why his fighter is always confused. It sounds like that idiot is suggesting there's a $5 million price tag if Manny comes up positive. That sounds suspicious. All I know is we welcome random testing as we always have."

Koncz said Pacquiao, who is training at trainer Freddie Roach's Wild Card Boxing Club in Hollywood, California, has so far submitted to two random tests by USADA.

Ellerbe said he was unsure how many times Mayweather has been tested but said he has seen the specimen collectors around Mayweather's Las Vegas gym "three or four times" since he began training for the fight.