(RNN) - Lance Armstrong is returning to the United States from Paris, where he was preparing for a triathlon, after being informed he would not be allowed to compete in the event because of doping allegations.
Armstrong told the Associated Press in a phone interview on Wednesday that he is returning to the states in the aftermath of the U.S. Anti-Doping Agency accusing the seven-time Tour de France winner of using performance-enhancing drugs.
He also said that is considering every possible option to defend himself.
Delphine Vivet, a spokesman for Ironman France, told the Associated Press that Armstrong was informed Wednesday that he is out of the June 24 race in Nice, France, because of the new USADA proceedings against him.
The World Triathlon Corporation stated in a news release, "Our rules, as stated in the WTC Professional Athlete Agreement and Waiver, dictate an athlete is ineligible to compete during an open investigation. Armstrong is therefore suspended from competing in WTC-owned and licensed races pending further review."
If the USADA finds Armstrong guilty, he could be stripped of all his titles. The organization claims to have 10 former teammates and support staff willing to testify against Armstrong.
He has until June 22 to respond to the charges in writing, and he is waiting to see the evidence USADA has found, according to the Associated Press.
Armstrong, who has successfully fought cancer as well as rumors that he used performance-enhancing drugs for several years, refuted the claims in a statement.
"I have never doped, and, unlike many of my accusers, I have competed as an endurance athlete for 25 years with no spike in performance, passed more than 500 drug tests and never failed one," Armstrong said. "That USADA ignores this fundamental distinction and charges me instead of the admitted dopers says far more about USADA, its lack of fairness and this vendetta than it does about my guilt or innocence."
USADA polices doping for all Olympic sports in the United States.
In a 15-page letter obtained by the Washington Post, USADA alleges it collected blood samples from Armstrong in 2009 and 2010 that were "fully consistent with blood manipulation including EPO use and/or blood transfusions."
The Post reported "Armstrong has been immediately banned from competing in triathlons, a sport he took up after he retired from cycling in 2011."
The USADA letter alleges that Armstrong and three doctors, one trainer and a team manager engaged in a massive doping conspiracy from 1998 to 2011.
Armstrong faces a lifetime ban from cycling if he is found guilty of using PED's.
"These charges are baseless, motivated by spite and advanced through testimony bought and paid for by promises of anonymity and immunity," Armstrong went on to say in his statement. "Although USADA alleges a wide-ranging conspiracy extended over more than 16 years, I am the only athlete it has chosen to charge."
USADA does not have the power to levy criminal charges against athletes, but it can strip titles and ban them from competition. Athletes may request a hearing when charged with wrongdoing by USADA. If an athlete loses, he or she may appeal to the Court of Arbitration for Sport, an international arbitration body.
A nearly two-year probe by federal prosecutors in the case closed in February without official charges being brought against Armstrong or his teammates.
Three days after the federal case was dropped, Alberto Contador was stripped of his 2010 Tour de France title and banned from the sport for two years after he was found guilty of doping.
Contador was the second rider ever to be stripped of a title in one of the sport's most prestigious races. The first was Floyd Landis, a former teammate of Armstrong, who lost his 2006 title after testing positive for testosterone.
On Feb. 10, Ironman partnered with Armstrong's foundation, LiveStrong, to help raise money for cancer survivors.
LiveStrong CEO Doug Ulman issued a statement of support on the foundation's website.
"In our eyes, Lance will always remain a champion," Ulman said. "Our thoughts are with Lance and his family as they face what can only be a very frustrating and difficult time as a result of USADA's actions."
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