NEW YORK: Tyler Hamilton, who was allowed to keep his Athens Olympics gold medal despite failing a doping test, has finally confessed to cheating and accused other top cyclists including Lance Armstrong of doing the same. In an interview to be aired by “60 Minutes” Sunday, Hamilton ended years of denials by finally admitting to using performance-enhancing drugs, but insisted he was not alone. The 40-year-old said he witnessed his former teammate Armstrong inject himself with a blood-booster during the 1999 Tour de France, which Armstrong won. “(Armstrong) took what we all took ... there was EPO (erythropoietin)... testosterone... a blood transfusion,” Hamilton said in an excerpt released by the CBS television network. “I saw (EPO) in his refrigerator. I saw him inject it more than one time, like we all did, like I did many, many times.” Hamilton has surrendered his 2004 Olympic gold medal, the US Anti-Doping Agency (USADA) said Friday. The International Olympic Committee (IOC) earlier Friday said it also was studying the issue. Armstrong, who won the Tour de France seven times, has always denied taking banned substances but has repeatedly had to fend off accusations despite having never failed a drugs test. His lawyer Mark Fabiani told Reuters Thursday that Hamilton's accusations about Armstrong were untrue. “Hamilton is actively seeking to make money by writing a book and now he has completely changed the story he has always told before so that he could get himself on “60 Minutes” and increase his chances with publishers,” Fabiani said. “But greed and a hunger for publicity cannot change the facts: Lance Armstrong is the most tested athlete in the history of sports.” Armstrong reiterated Fabiani's view on his Twitter page. “20+ year career. 500 drug controls worldwide, in and out of competition. Never a failed test. I rest my case,” he tweeted. World cycling's governing body the UCI said it had only just become aware of the accusation. “UCI heard of it for the first time today in the press,” spokesman Enrico Carpani said when contacted. “Only Mr. Hamilton and Mr. Armstrong are in a position to comment on it.” Hamilton said he had decided to come clean after he was subpoenaed by a grand injury currently investigating Armstrong after another of his former teammates pointed the finger at him. In an open letter to his friends and family published by various media, Hamilton wrote: “Last summer, I received a subpoena to testify before a grand jury. Until that moment I walked into the courtroom, I hadn't told a soul. “My testimony went on for six hours. For me, it was like the Hoover Dam breaking. I opened up; I told the whole truth, and nothing but the truth. And I felt a sense of relief I'd never felt before.” The Texan was diagnosed with testicular cancer in 1996 but recovered and returned to racing, winning the Tour de France an unprecedented seven consecutive years, from 1999 to 2005. He quit when he was at the top, but made a comeback in 2009, at 37, saying he partly missed the thrill of competition but was driven by a greater cause, to help promote cancer awareness.