( CNN ) -- Champion cyclist Lance Armstrong said Wednesday the U.S. Anti-Doping Agency intends to `` dredge up discredited '' doping allegations against him in a bid to strip him of his seven Tour de France victories . The Washington Post said it received a copy of a 15-page agency letter sent Tuesday to Armstrong and several others . As a result of the allegations , Armstrong was immediately banned from competing in triathlons , a sport he took up after retiring from professional bicycling , the newspaper reported on its website . Armstrong , as he has in the past , said he has never engaged in doping . `` 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 , '' Armstrong said on his website . `` 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 . '' Justice Department prosecutors in February said they closed a criminal investigation after reviewing allegations against Armstrong . They had called witnesses to a federal grand jury in Los Angeles , but they apparently determined they lacked evidence to bring a charge that Armstrong used performance-enhancing drugs . Armstrong was accused of using such drugs by other riders , but never failed a drug test . `` 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 Wednesday . According to the Post , the U.S. Anti-Doping Agency alleged it collected blood samples from Armstrong in 2009 and 2010 that were `` fully consistent with blood manipulation including EPO use and/or blood transfusions . '' The allegations were previously unpublicized , according to the Post . Opinion : Why fans should n't forgive Armstrong . The letter says Armstrong and five former cycling team associates engaged in a doping conspiracy from 1998 to 2011 , the Post reported . Riders will testify that Armstrong used EPO , blood transfusions , testosterone and masking agents , and that he distributed and administered drugs to other cyclists from 1998 to 2005 , the Post quoted the letter as saying . In a statement obtained by CNN , U.S. Anti-Doping Agency CEO Travis T. Tygart said the five other people , formerly associated with the U.S . Postal Service pro cycling team , are three team doctors and two team officials . The letter included written notice of alleged anti-doping rule violations , Tygart said . `` USADA only initiates matters supported by the evidence , '' 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 . '' All named individuals are presumed innocent until proven otherwise , he added . His statement did not mention anything about Armstrong 's status as a triathlete . According to its website , the quasi-government agency is recognized as the official anti-doping agency for Olympic , Pan American and Paralympic events in the United States . Armstrong lashed out at the organization , saying it has `` self-written rules '' and that it punishes first and adjudicates the facts later . Armstrong has been dogged by allegations of drug abuse in recent years , with compatriot Floyd Landis -- who was found guilty of doping in the 2006 Tour de France , resulting in him being stripped of the title -- making a series of claims last year . Armstrong came out fighting once again in May 2011 in the face of fresh allegations made on the CBS News `` 60 Minutes '' show by another American , Tyler Hamilton . In the CBS interview , Hamilton -- who retired in 2009 after twice testing positive himself -- says he first saw Armstrong use blood boosting substance EPO in 1999 , the year of his first Tour de France victory . `` I saw it in his refrigerator , '' Hamilton told the American news program . `` I saw him inject it more than one time like we all did , like I did many , many times . '' On his Twitter page , Armstrong at the time said he never failed a drug test . Ex-teammate : I saw Lance Armstrong inject banned substances . CNN 's Terry Frieden and Jason Durand contributed to this report .
Anti-doping agency investigating Lance Armstrong , five others . Armstrong says the agency is on a vendetta . Agency says it only initiates matters `` supported by the evidence ''