The U.S. Anti-Doping Agency will bring doping charges against cycling legend Lance Armstrong, according to media reports.

Armstrong won the Tour de France seven times before retiring from cycling last year. He could face a lifetime ban from the sport if he is found guilty of using performance-enhancing drugs, The Associated Press reported.

The charges came months after federal prosecutors closed a two-year criminal investigation of Armstrong without indicting him, the AP said.

Armstrong maintained his innocence. "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," he said.

On his website, LanceArmstrong.com, Armstrong released a statement saying the charges are "baseless" and "motivated by spite."

"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," the statement said. "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."