AUSTIN, Texas (MCT) — The U.S. Anti-Doping Agency has filed drug conspiracy charges against Lance Armstrong, putting his seven Tour de France titles in jeopardy and at least temporarily ending his recent re-emergence in triathlons.

The agency, which regulates doping in U.S. Olympic sports, alleges that the 40-year-old Armstrong, his long-time team director Johan Bruyneel, two team doctors, a trainer and a medical adviser were part of an organized doping scheme dating back to possibly 1996.

The agency believes Armstrong possessed, distributed and encouraged others to use performance-enhancing drugs. It also said the circumstances are "aggravated," which is why they will ask for a lifetime ban.

No other cyclist was charged, although in the letter that was leaked to a handful of national media outlets, USADA said it had testimony from at least 10 unidentified riders.

Two of those riders believed to have given testimony are Floyd Landis and Tyler Hamilton. They are former friends of Armstrong's who were suspended from cycling for doping after they had parted ways with Armstrong's team. They have made fairly recent confessions of their own drug use, after long-time denials, while implicating Armstrong.

Armstrong, who has been in southern France for the past week training for a triathlon, issued a statement calling the USADA charges the result of a long-held "vendetta" against him.

"These are the very same charges and the same witnesses that the Justice Department chose not to pursue after a two-year investigation," Armstrong said.

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"… 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. 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."

The next step is for Armstrong to answer the charges. The deadline is June 22.

There is an eight-year statute of limitation for doping charges. Armstrong won his Tour championships from 1999-2005.

USADA said it's asking for the statute of limitations to be waived because of recent eyewitness testimony and the severity of the allegations.

USADA claimed that the agency had evidence that Armstrong's blood tests in 2009-10 showed manipulation and use of banned doping products.