The U.S. Anti-Doping Agency brought formal doping charges against former cyclist Lance Armstrong in an action that could cost him his seven Tour de France titles, according to a letter sent to Armstrong and several others.

As a result of the charges, Armstrong has been immediately banned from competition in triathlons, which he took up after his retirement from cycling in 2011.

In the 15-page charging letter obtained by the Post on Tuesday, the agency made previously unpublicized allegations against Armstrong, alleging it collected blood samples from Armstrong in 2009 and 2010 that were "fully consistent with blood manipulation including EPO use and/or blood transfusions." Armstrong has never tested positive.

Armstrong, 40, has fought off doping accusations for more than a decade, including coming out on top when a two-year federal investigation into his alleged doping-related crimes was dropped four months ago. This time, though, the accuser is the anti-doping agency, which does not have the power to bring criminal charges but does have the power to strip him of the accolades that helped make him the most famous cyclist in history.

If its charges are upheld, the agency -- a quasi-governmental organization that oversees anti-doping mostly in Olympic sports -- could also levy a lifetime ban on him from competing in elite events.

"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," said Armstrong, calling the charges "this vendetta."

More than 10 witnesses

USADA's letter, dated June 12, alleges that Armstrong and five former cycling team associates -- three doctors including Italian physician Michele Ferrari, one trainer and team manager Johan Bruyneel -- engaged in a massive doping conspiracy from 1998 to 2011, and that "the witnesses to the conduct described in this letter include more than ten (10) cyclists ..."

All of the six, including trainer Jose Pepi Marti of Switzerland and doctors Pedro Celaya of Luxembourg and Luis Garcia del Moral of Spain, face competition bans. USADA put all of the alleged violations in one letter, it said, because it considers the six defendants part of a "long running doping conspiracy."

The letter specifically alleges that "multiple riders with firsthand knowledge" will testify that Armstrong used the blood booster Erythropoietin, or EPO, blood transfusions, testosterone and masking agents, and that he distributed and administered drugs to other cyclists from 1998 to 2005. The letter alleges that numerous witnesses will testify that Armstrong also used human growth hormone before 1996.

"These charges are a product of malice and spite and not evidence," Robert Luskin, Armstrong's attorney, said Wednesday. "Nothing else explains the fact ... they allege an overarching doping conspiracy among four teams over 14 years and Lance is the only rider that gets charged."

Armstrong competed for the U.S. Postal Service team and later the Discovery Channel team from 1998 to 2005. In 2009, he rode for the Astana Cycling Team and on RadioShack's team in 2010-11.

The letter further claims that Martial Saugy, the director of an anti-doping lab in Switzerland, stated that Armstrong's urine sample results from the 2001 Tour of Switzerland indicated EPO use. Saugy said last year that Armstrong's sample was merely "suspicious," a designation that meant it could not be called positive. Further analysis with modern methods might bring clarity, Saugy said, but the sample no longer exists.

"We did not do the additional analysis. It will never be sufficient to say, in fact, it was positive," Saugy said then. "I will never go in front of a court with that type of thing."

Luskin said the agency last week asked Armstrong to meet with anti-doping officials. Armstrong declined, believing USADA was not interested in his testimony but rather a confession, Luskin said.

USADA chief executive Travis Tygart said, "We do not choose whether or not we do our job based on outside pressures, intimidation or for any reason other than the evidence. ... As in every USADA case, all named individuals are presumed innocent. ... If a hearing is ultimately held then it is an independent panel of arbitrators, not USADA that determines whether or not these individuals have committed anti-doping rule violations as alleged."

Though the World Anti-Doping Agency places an eight-year statute of limitations on doping allegations, USADA argues that evidence of banned acts outside of the eight-year limit can be used to corroborate evidence within the limit, and the statute of limitations can be waived when the alleged violations were fraudulently concealed.

Armstrong, who won his last tour title in 2005, has taken up competition in ironman triathlons, and was scheduled to compete in the Ironman France in Nice on June 24.

'Just a question of time'

News about the charges wasn't a big deal among racers in St. Paul as they prepared for Wednesday evening's Criterium race, which is part of the five-day Nature Valley Grand Prix. "There's been lots of stories over many years about his doping," said racer Anne-Marie Morin from Quebec. "It was just a question of time before he was charged."

But for some on the racing circuit, it's much ado about something that may or may not have happened too long ago.

"His last tour [win] was 2005. That was seven years ago," said Emile Abraham, a member of the Rossetti Devo team based in Alabama. "This is kind of a surprise because he's done so many tests. He was tested before tours. He was tested during tours. He was tested after tours. And now years have passed. It's done and gone. ... If they had caught him in the act at the time, that would have been different. People are still going to remember that he won the tour seven times even if they take his titles away."

Racer Pete Custer from Washington questioned the reason for charging him now. "It's silly," he said. "I don't see how this benefits cycling." The sport of cycling is already "drastically cleaner," Custer said. "Constant and consistent drug testing has made the difference and now you're seeing more realistic performances. There are no super human performances."

Even with those who believe Armstrong enhanced his performances with drugs, the charges weren't welcomed. "Who cares?" said Jonas Nygard, a spectator and an amateur racer. "Everyone was cheating then. ... You want to think that he was clean, but it's not logical because he was competing against guys who were using cheating."

Staff writer Mary Lynn Smith and the New York Times contributed to this report.