SYDNEY - The final day of Paralympic competition yesterday was marred by the announcement of yet another doping scandal, this time relating to an American sprinter who tested positive for the performance enhancing drug nandrolone.

Brian Frasure, an amputee who has trained regularly with the American Olympic track star, Marion Jones, was stripped of his silver medal in the 200m and banned from competition for four years.

Earlier in the Games, nine powerlifters were expelled for taking a variety of performance-enhancing substances.

They were the first doping cases to come to light since Barcelona in 1992, when five athletes including a member of the American wheelchair basketball team, failed drug tests.

The International Paralympic Committee said that its Medical and Anti-Doping Commission accepted Frasure's assertion that he had inadvertently taken nandrolone – an anabolic steroid – in dietary supplements, but added that athletes should ensure they competed without using banned drugs.

Frasure, from Maiden, North Carolina, also won silver in the 100m final of his class last week, but he will be allowed to keep that medal because his test after that race was negative.

Both he and the powerlifters, who were all identified in out-of-competition tests carried out before the Games opened, will miss the Athens Paralympics in 2004.

The IPC medical officer, Michael Riding, said that the US National Paralympic Committee should have conducted out-of-competition tests on its athletes, as the US Olympic Committee did before the Sydney Games.

Riding said: "Frasure insists this was not deliberate use, and we accept that, but he was pretty foolish to use a supplement. As an élite athlete, he should have been a bit smarter."

The US team released a statement saying that Frasure had been one of the world's top 100m runners in events for amputees over the past three years.

"We are disappointed that a positive drug test has occurred among our delegation," said the head of the US team, Andy Kostanecki. "We support the work of the IPC Medical Commission and are committed to doing our part in eliminating the use of performance-enhancing drugs in sport."

The powerlifters were from various countries, including Bulgaria, Romania, Russia and Iran, and included two women who were to have taken part in the inaugural Paralympic women's powerlifting tournament.