The U.S. Olympic Committee (USOC) has identified 24 athletes who tested positive for banned drugs and then won medals at the Olympic Games over the last two decades, the Los Angeles Times has reported.
But, according to documents obtained by the newspaper, the USOC concluded there is no evidence of a widespread or systematic cover-up.
The paper's web site reported on Wednesday that the USOC has indicated that in all but one of the cases the athlete had "already served a suspension or received other appropriate discipline under the applicable rules".
The USOC's full report is due to be presented in Lausanne on Thursday at a meeting of the International Olympic Committee's (IOC) executive board.
The one athlete said not to have been disciplined is referred to as "the case of the 'unidentified' U.S. athlete who won a medal in Sydney".
The Los Angeles Times alleged in August that 400 metres world champion Jerome Young was the 'unidentified' athlete who tested positive for the banned steroid nandrolone in 1999.
Young, who won a gold medal as a member of the men's 4x400 relay team at Sydney in 2000, has denied ever committing a doping offence.
The LA Times says there is no documentation in USOC files offering a reasonable explanation for USA Track & Field's decision to exonerate Young.
The IOC's director-general Francois Carrard told reporters in Lausanne on the first day of the executive board's meeting on Wednesday that they wanted the USOC to reconsider the case "as quickly as possible".
The USOC report, says the LA Times, found the overwhelming number of the 24 positive tests were for stimulants commonly found in over-the-counter cold medicines. The names of most of the 24 athletes were not disclosed.
The report was prepared in response to long-standing concerns about an alleged U.S. cover-up, which U.S. authorities have denied.
USOC spokesman Darryl Seibel was quoted by the LA Times as saying: "These cases were adjudicated in accordance with the applicable rules of the time. There was no cover-up. There was no attempt to cover anything up."