Bas Czerwinski / AP

Lance Armstrong has been accused of using drugs during his Tour de France winning streak from 1999-2005.

Lance Armstrong dismissed as "nonsense" a reported claim by Greg LeMond that the seven-time Tour de France champion tried to pay someone $300,000 to say LeMond used a banned drug.

LeMond, a three-time Tour de France champion, told the German newspaper Sueddeutsche Zeitung's weekend issue that Armstrong tried to implicate him "by all means" in a scandal involving EPO, a performance enhancer.

LeMond refused to reveal the identity of the person who was allegedly offered money by Armstrong, saying he still works in cycling.

Armstrong dismissed the accusation after Sunday's 14th stage of the Tour.

"That's absolutely nonsense — $300,000?" Armstrong said, when asked by The Associated Press about the allegations. "Come on. I know (about the report). But he says a lot."

"That's just another thing," he said, alluding to years of antagonism between the two American Tour champions.

According to a report Friday in the Daily News of New York, LeMond has been served with a grand jury subpoena as part of a federal investigation of possible fraud and doping charges against Armstrong and his associates.

The federal investigation was spurred by accusations by Floyd Landis, a former teammate of Armstrong's on the US Postal team, in a series of emails sent to cycling and doping officials this spring.

Landis, who was stripped of his 2006 Tour title for doping, said the use of banned substances was common on the team. Armstrong has denied those allegations and has questioned Landis' credibility.

'It's the beginning of the end'
LeMond also told the French newspaper Journal Du Dimanche that the federal investigation will bring about the Armstrong's downfall.

Lionel Cironneau / AP file Greg Lemond, center, races down the Champs Elysees in Paris in the 23rd and last stage of the Tour de France on July 27, 1986. Lemond won the 73rd Tour de France, becoming the first American to win the race.

"Given everything that he has been accused of recently, I'm even surprised he decided to race the Tour. I don't know how he's managed to stay concentrated on the race. It will be interesting to see if he collaborates with the investigation.

"The federal investigation is very serious, more than people believe."

LeMond told the Journal Du Dimanche that he believes LeMond and that Landis's friends have been threatened by Armstrong.

"Listen, Landis spoke out because Armstrong was going after him. He made threats against his (Landis's) friends," LeMond said.

"I believe Landis because everything he's said, I've already heard. There's a major difference between a guy like Ivan Basso (who was banned for two years for doping) and Armstrong. Basso doesn't threaten people.