Boxing:Floyd Mayweather's camp have claimed the American's planned fight with Manny Pacquiao is "in jeopardy".
Golden Boy Promotions chief executive Richard Schaefer said Pacquiao's promoters Top Rank have stated that the Filipino fighter will not agree to blood-testing in the 30 days prior to the fight, which has been expected to take place in March.
Schaefer said: "Todd (Top Rank president Todd duBoef) told me that Pacquiao has difficulty with taking blood and doesn't want to do it so close to the fight.
"He, Pacquiao, would only agree to have blood drawn before the kick-off press conference and after the fight."
Mayweather's management have requested that the fighters submit to blood-testing prior to the bout, to ensure both men are clean.
Schaefer added: "It is unfortunate to hear this from Manny Pacquiao's representatives, particularly since, as of today, both parties had worked out all other issues related to this fight."
Mayweather urged Pacquiao to agree to the blood testing.
"I understand Pacquiao not liking having his blood taken, because frankly I don't know anyone who really does," said Mayweather.
"But in a fight of this magnitude, I think it is our responsibility to subject ourselves to sportsmanship at the highest level."