Manny Pacquiao has accepted Floyd Mayweather's challenge for a showdown in May, but barriers remain in the way of a possible super-fight.
On Wednesday, Mayweather demanded Pacquiao "give the world what they want to see" and agree to a bout on 5 May.
And while Pacquiao said he wanted the fight, he said he favours a date in late May and suggested Mayweather could not guarantee his side of the purse.
"This is the fight the world wants," said Philippine superstar Pacquiao.
"[But] Mayweather wants a guaranteed purse so what he has to do is get a promoter who can give him the guarantee.
"I don't have problems getting a guarantee because I have a promoter who will give me my guaranteed purse.
“Manny Pacquiao I'm calling you out let's fight May 5 and give the world what they want to see... Step up Punk”
"If he gets a guarantee, then we are going to share the revenue on a 50-50 basis."
Pacquiao's promoter Bob Arum added: "There is no problem on our part - the problem is on Mayweather's.
"Mayweather needs somebody on his side that's going to guarantee his purse. Mayweather has nobody on his side and GBP (Oscar de la Hoya's Golden Boy Promotions) is not going to guarantee his purse."
Arum and Pacquiao's financial advisor, Michael Koncz, want a bout in late May to coincide with the completion of a 45,000-seater arena in Las Vegas.
The MGM Grand, where Mayweather is booked to fight on 5 May, has a capacity of only 17,000 and Koncz claims an additional $30m (£13m) could be raised if the bout took place in the new venue.
"Why would I tell Manny to fight on 5 May and throw away a percentage of $30m? That's crazy," said Koncz.
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"This was boxing's big chance to emerge from the slump. If the dunces can't sort this mess out, many will think the sport is not worth forgiving."
Last week, five-weight world champion Mayweather had a 90-day jail term deferred so that he could fulfil a pre-arranged date at the MGM Grand. He will now begin his sentence on 1 June.
The WBC welterweight champion subsequently used
his Twitter account
to challenge Pacquiao.
"Step up Punk," said the undefeated American. "Manny Pacquiao I'm calling you out let's fight May 5 and give the world what they want to see (sic)."
A year ago,
when Pacquiao, 33, pulled out after Mayweather demanded random drugs tests before the bout.
At the time Arum called Mayweather "a psychological coward who doesn't want to fight anybody who has a chance of beating him", and predicted the bout would never take place.
But if the purse on offer matches the £25m-per-fighter deal that was rumoured to be on offer last year, the biggest payday in boxing history may prove persuasive.
Arum insisted that if there was to be no fight in late May against the American then he would move forward with a Pacquiao clash on 9 June against someone else.
He listed a rematch against Mexico's Juan Manuel Marquez or Puerto Rican Miguel Cotto, as well as Americans Tim Bradley and Lamont Peterson, as potential alternatives.
Seven-weight world champion Pacquiao fought Marquez for a third time in November
and retained his WBO title, although, as with the previous two fights, the decision was a controversial one.
Mayweather, who turns 35 next month, won the WBC title with
a fourth-round knockout of compatriot Victor Ortiz in September.