The U.S. Olympic Committee has filed an appeal with the Swiss-based Court of Arbitration for Sport (CAS) to block a decision that would strip Michael Johnson and the rest of the U.S. men's 4x400 relay team members of their 2000 Olympic gold medals because of a positive drug test by relay team member Jerome Young.

The USOC believes that only Young should relinquish his gold medal.

The world governing body of track and field (IAAF) recommended this summer that the entire relay team be penalized after a CAS ruling in June said Young should not have been allowed to compete. The International Olympic Committee did not act on the IAAF's recommendation during meetings in August, preferring to wait for the result of the USOC appeal.

Young, who tested positive for erythropoietin (EPO) this summer and faces a lifetime ban from the sport, tested positive for the steroid nandrolone in 1999 but was exonerated by a USA Track and Field appeals board in 2000 and was permitted to compete.

He ran an early round of the event and did not compete in the final.

The USOC filed the appeal along with relay-team members Johnson, Jerome Taylor and twins Alvin and Calvin Harrison. The Harrisons were recently banned for using drugs, with Alvin accepting a four-year ban and Calvin a two-year ban.

Meantime, the Russian Olympic Committee has asked CAS to strip American cyclist Tyler Hamilton of the time-trial gold medal he won at the 2004 Summer Games in an appeal filed last week because of a positive drug test.

The IOC said after the Games that Hamilton clearly tested positive for blood doping, but it dropped its case against him because of a lab mistake. Should Hamilton -- who has vehemently proclaimed his innocence -- be stripped of his medal, Russian Vyacheslav Ekimov, who won silver, would receive the gold.

-- Amy Shipley