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.

Armstrong on Thursday night dropped any further challenges to USADA's allegations that he took performance-enhancing drugs to win cycling's premier event from 1999-2005.

【新聞快訊】

美國(guó)傳奇車(chē)手阿姆斯特朗于當(dāng)?shù)貢r(shí)間周四在個(gè)人網(wǎng)站上發(fā)表聲明，宣布將放棄對(duì)自己服用禁藥指控的申訴。聲明中說(shuō)“在過(guò)去的三年里，我一直在接受調(diào)查，這已經(jīng)影響到了我的家庭，我的工作?！泵绹?guó)反興奮劑機(jī)構(gòu)（USADA）宣布將剝奪阿姆斯特朗的冠軍頭銜，對(duì)他終身禁賽。

對(duì)于他服用禁藥的質(zhì)疑，阿姆斯特朗則是極力否認(rèn)，辯稱(chēng)美國(guó)反興奮劑組織不具備追究他是否服用禁藥的管轄全力，同時(shí)聲稱(chēng)從美國(guó)憲法來(lái)看，反興奮劑機(jī)構(gòu)在仲裁過(guò)程中已經(jīng)侵犯了他的權(quán)利。

據(jù)來(lái)自美聯(lián)社的最新消息，阿姆斯特朗由于拒絕了美國(guó)反興奮劑機(jī)構(gòu)（USADA）的仲裁要求，USADA表示他們將會(huì)提出阿姆斯特朗終身禁賽的判決，并收回其所有的榮譽(yù)。

阿姆斯特朗在聲明中表示，在經(jīng)過(guò)多年的抗?fàn)幒螅约阂呀?jīng)“受夠了”，想不受干擾地投入到為抗癌患者們的工作當(dāng)中。阿姆斯特朗是一個(gè)癌癥基金會(huì)的創(chuàng)始人，該組織將在今年10月迎來(lái)15周年慶典和累計(jì)將近5億美元募捐的里程碑時(shí)刻。