Pacquiao-Mayweather fight off again

SARANGANI, Philippines, Jan. 7 (UPI) -- The potential welterweight title fight between Manny Pacquiao and Floyd Mayweather has been canceled after the sides could not agree on drug testing.

The bout, scheduled for March 13 in Las Vegas, likely would have been the richest in boxing history.

It was called off despite efforts by a mediator, retired federal judge Daniel Weinstein, to get the fighters to reach common ground on drug testing.

"The whole blood testing issue is just a facade to get Mayweather out of this fight," Pacquiao's American business adviser, Michael Koncz, claimed on his client's Web site.

Pacquiao filed a federal court defamation lawsuit against Mayweather and several members of Golden Boy Promotions when he felt comments from Mayweather's camp suggested he had used performance-enhancing drugs.

"I am very disappointed that we could not make this fight for the fans and I am angered because of the false accusations," Pacquiao said.