Eight years after winning Olympic medals in Athens, four track and field athletes from Eastern Europe were ordered to hand them back on Wednesday because of positive doping tests.

Lance Armstrong, meanwhile, can hold onto his bronze medal from the 2000 Sydney Games for a little while longer.

The International Olympic Committee executive board disqualified four athletes whose 2004 Athens Games doping samples were retested earlier this year and came back positive for steroids, including shot put gold medalist Yuriy Bilonog of Ukraine.

Also stripped were hammer throw silver medalist Ivan Tskikhan of Belarus and two bronze medalists - Russian women's shot putter Svetlana Krivelyova and Belarus discus thrower Irina Yatchenko.

The case of a fifth bronze medalist, weight lifter Oleg Perepechenov of Russia, remains pending.

The IOC said it will ask the International Association of Athletics Federations to get the four medals back and readjust the results and rankings from the Athens Games.

Until then, no decision will be taken on reallocating the medals. Adam Nelson of the United States finished second in the shot put in Athens behind Bilonog and would stand to move up to gold.

The IOC, meanwhile, held off stripping Armstrong of the bronze he won 12 years ago in the cycling road time trial in Sydney, citing procedural reasons.

Three-time Olympic gold medalist and five-time world champion Drew Ginn, 38, will retire from rowing to take up a national head coaching position in the sport in Australia.

SOCCER: In the Champions League, defending titlists Chelsea were eliminated despite a 6-1 win over Danish side Nordsjælland in London. The Blues needed a loss by Juventus to Shakhtar Donetsk in the Ukraine, but the Italian side won, 1-0.

Lionel Messi was taken off the field on a cart with a bone bruise to his left knee as host Barcelona was held to a 0-0 tie by Benfica. Messi has 84 goals for Barcelona and Argentina this year, one shy of Gerd Müller's 40-year-old record for most goals in a calendar year.

AUTO RACING: Tony Stewart has passed on Roger Penske's offer to race for the owner in the Indianapolis 500.

The three-time NASCAR champion said at the International Motorsports Industry Show in Indianapolis that he wouldn't attempt to race in both the Indy 500 and NASCAR's Coca-Cola 600 on the same day.

- Staff and wire reports