WBC and WBA welterweight champion Floyd Mayweather says he is "hopeful" a fight with Manny Pacquiao can happen, but an agreement has not yet been reached.
American Mayweather, 37, and Filipino Pacquiao, 36, recentlyexchanged phone numbers at a US basketball game.
"I haven't signed yet and he hasn't signed yet," said Mayweather.
Eight-division world champion Pacquiao, and Mayweather, a world champion at five weights, are considered the best fighters of their generation.
"It's just been speculations and rumours," Mayweather added. "But I'm hopeful we can make the fight happen."
Pacquiao's publicist Fred Sternburg recently said a bout between the two still has "a long way to go" but that there has been movement "in a positive direction".
It followed reports Pacquiao had agreed terms on a 2 May bout in Las Vegas.
One stumbling block has been Mayweather's insistence on a strict blood-testing programme during training, but Pacquiao said those demands cast him in a bad light as a suspected cheat.
Manny Pacquiao and Floyd Mayweather were both sitting courtside as Miami took on Milwaukee Bucks in an NBA contest in January