Tim Montgomery, the 100-meter world record holder, asked sport's highest arbitration panel to review charges of steroid use that might end his career.

Montgomery and three other athletes were accused of using steroids by the U.S. Anti-Doping Agency as part of the organization's efforts to ensure that the U.S. team at the Athens Olympics is drug free.

Montgomery's lawyer said his client's case will go to the Court of Arbitration for Sport in Lausanne, Switzerland. Rulings by that panel can't be appealed.

The sprinter bypassed review by a three-member American Arbitration Association panel, where USADA never has lost in 17 cases.

"By turning to CAS, we hope that Tim will have the best opportunity to clear his name in a fair and impartial proceeding," his attorney, Howard Jacobs, said in an e-mailed statement.

The agency is seeking lifetime bans on Montgomery, world indoor 200-meter champion Michelle Collins, former relay world champion Chryste Gaines and Olympic 400-meter silver medalist Alvin Harrison. None of them has failed drug tests and all have denied using banned performance-enhancing substances.

Pakistani Boxer Banned

Nauman Karim, a Pakistani declared Asia's best boxer this year, tested positive after the South Asian Federation Games in Islamabad, Pakistan, in April, said Anwar Chowdhry, president of Pakistan's boxing federation.

Karim said he used the drug Cannaboids before and during the event but said he had not known it was banned, Chowdhry said.

The Pakistan Olympic Association banned the flyweight for one year and disqualified him from the country's squad. Karim also was stripped of his medals from the SAF Games.

Last year, Karim won a bronze medal in the world boxing championships in Thailand.

"He was our top hope in Athens," Chowdhry said. "I am deeply shocked."

The boxing federation also warned three other boxers -- Karim's elder brother Faisal Karim, Asian Games gold medalist Mohammad Meharullah and Muzaffar Iqbal -- after they tested positive for the same drug.

Diamond to Represent Australia

Michael Diamond, a trap shooting gold medalist at the past two Summer Games, was approved yesterday to represent Australia in Athens. Diamond lost months of training and the chance to compete in Olympic selection events because of assault charges by his former girlfriend. He was cleared in January.

Diamond has a chance to become the third Australian to win gold medals in the same event in three consecutive Summer Games.