London ? In the wake of fresh doping allegations against Lance Armstrong, cycling’s world governing body and one of his former teammates came to the defense of the seven-time Tour de France champion on Monday.

Tyler Hamilton, another ex-teammate of Armstrong, says he witnessed the American take performance-enhancing drugs before or during the 1999, 2000 and 2001 Tours while with the U.S. Postal team.

However, team rider Viatcheslav Ekimov says he never saw Armstrong do any of the things Hamilton described.

The International Cycling Union also denied claims from Hamilton that it helped cover up a positive sample submitted by Armstrong at the Tour de Suisse in 2001.

“The UCI is deeply shocked by the seriousness of the allegations made on the ’60 Minutes’ program aired by U.S. television network CBS,” the organization said in a statement. “The allegations of Mr. Tyler Hamilton are completely unfounded.”

Ekimov, who rode with Armstrong as he won the Tour from 2000-05 and is now RadioShack’s team manager, referred to Hamilton as a “liar” and suggested he has ulterior motives in making his revelations now.

“Behind his story is something,” Ekimov said. “First of all, it’s untrue. And behind his story is some money or some stimulation. Because why did this guy just crack now? Why didn’t he do it in 2005? … I call these guys liars. First they lie about the innocence, now they lie about something else.

“I think it’s just money. It seems to me like somebody really wants to kill Lance and put him down. There’s all this interest to find people who will say something.”

Hamilton twice has been banned for doping. Armstrong has denied doping and has never tested positive.

Hamilton said Armstrong told him of a positive sample he submitted in 2001, claiming the Texan made a deal with the UCI and they “figured out a way for it to go away.”

But the UCI “categorically rejected” the accusation, insisting it had “never altered or hidden the results of a positive test.” The organization also said Armstrong had never been notified of a positive finding.

“The UCI can only express its indignation at this latest attempt to damage the image of cycling by a cyclist who has not hesitated to abuse the trust of all followers of cycling on several occasions in the past,” the statement said.

“The UCI can only confirm that Lance Armstrong has never been notified of a positive test result by any anti-doping laboratory. … Once again, the UCI wishes to state that no manipulation or cover up has occurred in respect of its anti-doping procedures.”