The United States Anti-Doping Agency announced Friday that it has disqualified all of retired cyclist Lance Armstrong's competitive results from Aug. 1, 1998, to the present, including the record seven Tour de France titles he won in 1999-2005.

The USADA said in a statement that it made the decision after Armstrong chose not to appear before an arbitration panel to respond to doping charges.

The 40-year-old American, who retired in 2011, had until midnight Thursday to respond to the accusations.

The USADA said in a statement that in light of Armstrong's decision not to defend himself against the charges, the agency was obligated under applicable rules to disqualify his past results and ban him from any future competition.

"Nobody wins when an athlete decides to cheat with dangerous performance enhancing drugs, but clean athletes at every level expect those of us here on their behalf, to pursue the truth to ensure the win-at-all-cost culture does not permanently overtake fair, honest competition," USADA CEO Travis T. Tygart said.

"Any time we have overwhelming proof of doping, our mandate is to initiate the case through the process and see it to conclusion as was done in this case," Tygart said.

The agency said the charges were based on evidence provided by "numerous witnesses" who said they had either personally observed Armstrong's "doping activity" or learned directly from the cyclist about his use of "EPO, blood transfusions, testosterone and cortisone during the period from before 1998 through 2005."

USADA also said there is "scientific data" that shows Armstrong's use of "blood manipulation, including EPO or blood transfusions," during his return to cycling in the 2009 Tour de France.

Armstrong, a cancer survivor who is regarded as one of the all-time greatest road cyclists, issued a statement Friday on his Web site categorically denying the doping accusations.

"There comes a point in every man's life when he has to say, 'enough is enough.' For me, that time is now. I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999," the statement read.

"Over the past three years, I have been subjected to a two-year federal criminal investigation followed by Travis Tygart's unconstitutional witch hunt. 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."

The lifetime ban means that Armstrong will not be allowed to participate in any activity or competition organized by any signatory to the World Anti-Doping Code, including the Switzerland-based International Cycling Union.

Retired Spanish cyclist Joseba Beloki, who stands to be named winner of the 2002 Tour de France in light of the USADA decision, expressed no interest in such a designation in remarks on Friday.

"It's a very long process. I'm proud of what I did in the Tour de France and this doesn't change anything. Races are won on the road," the former road racer said on Radio Eusadi, where he works as a commentator.

"I can only lay claim to my two third-place finishes and my second place in 2002. The Paris podium photo has already been taken," Beloki said.

Beloki recalled his hard fall during the 2003 Tour de France in which he suffered a broken elbow and wrist during the ninth stage and was forced to withdraw from the race. He was in second place at the time of the crash.

"Everything was ruined on the road to (the southeastern town of) Gap in 2003, which perhaps was the closest I ever got to winning a Tour." EFE