Cyclist Tyler Hamilton, who has accused Lance Armstrong of taking performance-enhancing drugs while they were teammates for the U.S. Postal Service cycling team, handed over his 2004 Olympic gold medal to the U.S. Anti-Doping Agency.

Mr. Hamilton, who rode with the U.S. Postal Service team from 1995 to 2001, admits doping during his career but denies doing so during the 2004 Olympics, according to a person close to the cyclist. Mr. Hamilton's lawyer, Chris Manderson, said Mr. Hamilton gave the medal to USADA because he didn't want any controversy about it to distract from his recent confession about doping or his accusations about Mr. Armstrong.

Mr. Hamilton, who rode with the U.S. Postal Service team from 1995 to 2001, admitted to doping during a television interview with CBS's "60 Minutes" to be aired Sunday. According to a clip, he also said he saw Mr. Armstrong inject EPO, a banned drug that boosts the number of red blood cells, more than once.

A lawyer for Mr. Armstrong said he denies the allegations. Mr. Hamilton is a "confessed liar in search of a book deal," Mr. Armstrong's lawyer said Thursday night. Mr. Armstrong has set up the website, www.facts4lance.com, to counter Mr. Hamilton's claims. Mr. Armstrong, 39 years old, won the Tour de France from 1999-2005. He retired earlier this year.

Mr. Armstrong has faced numerous doping allegations since he won his first Tour de France in 1999. However, cycling's governing body has never found him to have broken the rules.