The International Olympic Committee says 31 athletes from six sports could miss the Rio 2016 Olympics after a retest of 454 samples from the 2008 Beijing Games.
Russian athletes are expected to be among the individuals who could be banned after their samples from the Beijing Games tested positive for prohibited substances.
By stopping so many doped athletes from participating in Rio we are showing once more our determination to protect the integrity of the Olympic competitions so that the Olympic magic can unfold.
The IOC said the retests were conducted using the very latest scientific methods which were not available at the time of the 2008 Games.
250 samples from the London Games and samples from the Sochi 2014 Winter Games would also be retested after allegations of tarnished samples were made by Russia’s former top anti-doping scientist.
Samples from those athletes who could be promoted to medal status because of the disqualification of others will also be retested.
The IOC said this was a targeted re-testing on athletes likely to be at the Rio Games and those found to have tested positive would not compete.
However, the IOC said no names would be made public until athletes had been informed and a second sample tested as well.
“All these measures are a powerful strike against the cheats we do not allow to win. They show once again that dopers have no place to hide. By stopping so many doped athletes from participating in Rio we are showing once more our determination to protect the integrity of the Olympic competitions, including the Rio anti-doping laboratory, so that the Olympic magic can unfold in Rio de Janeiro,” said IOC President Thomas Bach.
The re-tests, a regular procedure by the IOC as it looks to use newer methods or look for new substances, were carried out together with the World Anti-Doping Agency and international federations.
The latest measures taken by the IOC come after Russia and Kenya were found to have breached anti-doping rules in recent months.
Russia was banned from athletics competition in November after a WADA commission report recommended the sanction.
Russian sports minister Vitaly Mutko said his country was “very sorry” and “ashamed” of cheating athletes who were not caught by its anti-doping systems.
The Rio Games run from August 5 to 21, 2016.
Reuters/ Press Agencies