The International Olympic Committee said Wednesday that it will retest samples from the games to search for a new blood-boosting drug at the center of the latest Tour de France scandals.

The move reflects the IOC's aggressive attempts to nab drug cheats not just during an Olympics, but weeks, months and even years later once new tests become available. Results and medals could be at stake.

"Our message is very clear," IOC president Jacques Rogge said in a statement. "The IOC will not miss any opportunity to further analyze samples retroactively. We hope that this will work as a strong deterrent and make athletes think twice before cheating."

The Beijing samples will be reopened and tested in particular for CERA, a new generation of the endurance-enhancing hormone EPO. The substance boosts an athlete's performance by increasing the number of oxygen-rich blood cells.

No test for CERA was available during the Beijing Games. But a new blood test developed by the French Anti-Doping Agency has since detected CERA in samples of Tour de France riders, and the IOC wants to go back and check whether it also was used in Beijing.

"The idea is to retest across the sports, not solely on cycling," IOC spokeswoman Emmanuelle Moreau said. "They will retest for all the new substances that are currently detectable, not only CERA."

IOC medical director Patrick Schamasch said the IOC will test blood samples for CERA, but other tests will also be carried out to detect new drugs which he declined to identify.

"We have indication of other substances," he said.

The IOC freezes and stores samples from the Olympics for eight years, leaving open the possibility to retest them when new detection methods are devised.

The IOC conducted more than 5,000 drug tests during the Beijing Games, including nearly 1,000 blood screenings.

All Beijing samples are currently being sent to the Olympic doping lab in Lausanne, Switzerland.

IOC medical officials haven't decided yet how many or which samples will be opened for reanalysis.

"You don't do it just by random," IOC medical commission chairman Arne Ljungqvist told the AP. "You have to base it on some suspicion. A number of blood samples were taken in Beijing. We will look into where we may have some suspicious parameters. Endurance events are of particular interest."

The time frame for the testing process hasn't been finalized. Logistics have to be worked out, including whether the tests will be analyzed in Lausanne or other labs.

"Our hope is to have this done during the coming few months," Ljungqvist said.

The IOC previously retested some samples from the 2002 Salt Lake City Winter Games to look for THG, the designer steroid at the center of the BALCO scandal. No positives were found.

Any athletes caught by new tests can be sanctioned retrospectively and be stripped of their results and medals.

"All undiscovered cheats will be shaking now," said Michael Vesper, director general of the German Olympic Sports Union.

The IOC has shown increasing willingness to retroactively punish doping cheats. U.S. athlete Marion Jones had to return her five medals from the 2000 Sydney Olympics after she admitted in federal court last year that she had been doping.

"Since we store the samples and have them at our disposal, we will not hesitate in doing further analysis," Ljungqvist said. "This is a message to people who are tempted to cheat that there may be something coming up soon or later."

Andy Parkinson, head of operations of Drug-Free Sport in Britain, said the initiative "sends a great message."

"Long gone are the days when an athlete gets a negative test after a competition and disappears with the medal forever," he said. "Athletes who cheat are not safe even eight years after competitions."

Officials confirmed on Tuesday that German rider Stefan Schumacher and Italians Riccardo Ricco and Leonardo Piepoli tested positive for CERA at the Tour de France. The three riders combined to win five of the Tour's 21 stages.

Swiss pharmaceutical giant Roche Holding AG, which manufactures the drug for use by kidney patients, said it had teamed up with the World Anti-Doping Agency since 2004 to help catch cheats using it for sports enhancement.

"We were very pleased that this collaboration with WADA has been productive," Roche spokeswoman Claudia Schmitt said on Wednesday.

Michael Ashenden, the Australian-based coordinator of the research consortium Science and Industry Against Blood Doping, helped develop the first doping test for EPO and another for blood tranfusion.

He said Thursday that he expects the IOC retesting to result in more positives.

"It wouldn't surprise me at all if we had more athletes caught," Ashenden said. "CERA is more easily detectable in blood than in urine. If there are some athletes that showed indications of it in urine, anticipate there will be even more of it in blood."

WADA president John Fahey agreed that retesting could result in more drug test positives.

"There's a distinct possibility that the retesting will bring out cases that weren't otherwise thought possible to detect," Fahey said on Thursday from his base in Sydney, Australia. "WADA believes that this is a very strong deterrent against any athlete who may be tempted to cheat."

The IOC disqualified six athletes for doping during the Aug. 8-24 Beijing Games _ Ukrainian heptathlete Lyudmila Blonska, Ukrainian weightlifter Igor Razoronov, Greek hurdler Fani Halkia, North Korean shooter Kim Jong Su, Spanish cyclist Isabel Moreno and Vietnamese gymnast Thi Ngan Thuong Do.

Three other cases are still pending. The IOC has given Belarusian hammer throwers Vadim Devyatovskiy and Ivan Tsikhan until Oct. 17 to provide more information explaining why they tested positive for testosterone. A decision is due shortly in the case of Polish canoeist Adam Seroczynski, who tested positive for clenbuterol.

In addition, dozens of athletes around the world were caught for doping before the Olympics in pre-games tests.