As many as 31 athletes from 12 countries spread across six sports could be banned from participating in the upcoming Summer Olympics in Rio de Janeiro for doping, the International Olympic Committee said on Tuesday. This comes after 454 doping samples from the 2008 Beijing Games were re-tested and came out positive.

The retests, which were carried out in collaboration with the World Anti-Doping Agency and international federations, were focused on athletes who could take part in this year's Games, the IOC said in a statement. As many as 250 samples from the 2012 London Olympics would also be re-tested soon, the statement added.

"All these measures are a powerful strike against the cheats we do not allow to win," IOC president Thomas Bach told the BBC. "They show once again that dopers have no place to hide. We keep samples for 10 years so that the cheats know that they can never rest. By stopping so many doped athletes from participating in Rio, we are showing once more our determination to protect the integrity of the Olympic competition," he added.