Floyd Mayweather has continued to ignite the flames under his rivalry with Manny Pacquiao by dubbing Pacman a cheater, during a press tour to promote his upcoming fight against Miguel Cotto.

Speaking in Puerto Rico during the first day of a three-day promotional trek for his May 5 contest in Las Vegas, Mayweather said:

Floyd Mayweather is not a cheater like Antonio Margarito or Manny Pacquiao.

You can watch Mayweather's remarks in the video below. Click to 4.25 in to see his words for Pacquiao.

Regarding his comments about Margarito it seems fairly clear that Mayweather was referring to the illegal hand wraps that Margarito was found to be using during his loss to Shane Mosley in 2009. It has been widely speculated that Margarito was using the hand wraps in his previous fight--when he knocked out Cotto.

As for Mayweather's comments about Pacquiao, it could be that he was referencing allegations about Pacquiao's use of steroids. Mayweather is currently the subject of a defamation suit, with Pacquiao alleging that the American unfairly accused him of using performance-enhancing drugs.

Mayweather, however, has in the past denied ever making the claims.

I've never said that Manny Pacquiao was taking steroids, I never said he was taking enhancement drugs, he said, according to ESPN.

The issue was first brought up over initial failed negotiations for a fight between the world's best pound-for-pound boxers. Mayweather had requested that Pacquiao submit to random drug testing in order for the match up to go ahead.

It's not just Pacquiao, it's sports, period, Mayweather said. If you look at sports in the Olympics, they're cheating. Everyone is cheating. And I never once said Manny Pacquiao was cheating, only thing I said was this: Me and any other opponent I face must take the test.

Mayweather has yet to explain his comments, but with the defamation suit ongoing, his words are sure to be closely scrutinized by Pacquiao's team.

The remarks also call into doubt Pacman's comments yesterday that a Mayweather Vs. Pacquiao match-up could still happen this year. The latest round of negotiations broke down over the share of lucrative pay-per-view revenue.

Pacquiao is scheduled to take on the undefeated Timothy Bradley on June 9.