London: Seven-time Tour de France winner Lance Armstrong has furiously denied a former teammate`s new claim that he took performance-enhancing drugs.
Using the social network Twitter, the Daily Mail quoted Armstrong, as saying: "20+ year career. 500 drug controls worldwide, in and out of competition. Never a failed test. I rest my case."
He was responding to fellow cyclist Tyler Hamilton`s charge that both Hailton and Armstrong regularly took the performance-enhancing drug EPO.
The new accusations come a year after Floyd Landis, another former team-mate, made similar allegations of drug use by Armstrong.
EPO boosts the number of red blood cells in the body and increases endurance.
Federal authorities are now investigating whether Armstrong and his former U.S. Postal team did take part in a systematic doping program.
Armstrong`s legal representative Mark Fabiani said: "Hamilton is actively seeking to make money by writing a book and now he has completely changed the story he has always told before so that he could get himself on 60 Minutes and increase his chances with publishers."