AUSTIN, Texas (AP) — With stunning swiftness, the U.S. Anti-Doping Agency said Thursday night it will strip Lance Armstrong of his unprecedented seven Tour de France titles after he dropped his fight against drug charges that threatened his legacy as one of the greatest cyclists of all time.

Travis Tygart, USADA's chief executive, said Armstrong would also be hit with a lifetime ban on Friday. Under the World Anti-Doping Code, he could lose other awards, event titles and cash earnings while the International Olympic Committee might look at the bronze medal he won in the 2000 Games.

Armstrong, who retired last year, effectively dropped his fight by declining to enter USADA's arbitration process — his last option — because he said he was weary of fighting accusations that have dogged him for years. He has consistently pointed to the hundreds of drug tests he passed as proof of his innocence while piling up Tour titles from 1999 to 2005.

"There comes a point in every man's life when he has to say, 'Enough is enough.' For me, that time is now," Armstrong said. He called the USADA investigation an "unconstitutional witch hunt."

"I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999," he said. "The toll this has taken on my family and my work for our foundation and on me leads me to where I am today — finished with this nonsense."

USADA reacted quickly and treated Armstrong's decision as an admission of guilt, hanging the label of drug cheat on an athlete who was a hero to thousands for overcoming life-threatening testicular cancer and for his foundation's support for cancer research.

"It is a sad day for all of us who love sport and athletes," Tygart said. "It's a heartbreaking example of win at all costs overtaking the fair and safe option. There's no success in cheating to win."

Tygart said the agency had the power to strip the Tour titles, though Armstrong disputed that.

"USADA cannot assert control of a professional international sport and attempt to strip my seven Tour de France titles," he said. "I know who won those seven Tours, my teammates know who won those seven Tours, and everyone I competed against knows who won those seven Tours."

Still to be heard from was the sport's governing body, the International Cycling Union, which had backed Armstrong's legal challenge to USADA's authority and in theory could take the case before the international Court of Arbitration for Sport.

Tygart said UCI was "bound to recognize our decision and impose it" as a signer of the World Anti-Doping Code.

"They have no choice but to strip the titles under the code," he said.

USADA maintains that Armstrong has used banned substances as far back as 1996, including the blood-booster EPO and steroids as well as blood transfusions — all to boost his performance.

The 40-year-old Armstrong walked away from the sport in 2011 without being charged following a two-year federal criminal investigation into many of the same accusations he faces from USADA.

The federal probe was closed in February, but USADA announced in June it had evidence Armstrong used banned substances and methods — and encouraged their use by teammates. The agency also said it had blood tests from 2009 and 2010 that were "fully consistent" with blood doping.

Included in USADA's evidence were emails written by Armstrong's former U.S. Postal Service teammate Floyd Landis, who was stripped of his 2006 Tour de France title after a positive drug test. Landis' emails to a USA Cycling official detailed allegations of a complex doping program on the team.

USADA also said it had 10 former Armstrong teammates ready to testify against him. Other than suggesting they include Landis and Tyler Hamilton, both of whom have admitted to doping offenses, the agency has refused to say who they are or specifically what they would say.

"There is zero physical evidence to support (the) outlandish and heinous claims," Armstrong said. "The only physical evidence here is the hundreds of (doping) controls I have passed with flying colors."

Armstrong sued USADA in Austin, where he lives, in an attempt to block the case and was supported by the UCI. A judge threw out the case on Monday, siding with USADA despite questioning the agency's pursuit of Armstrong in his retirement.

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