After retests of samples from the 2008 Beijing Olympics, 31 athletes from 12 countries in six sports could be banned from this summer's Olympic Games in Rio de Janeiro, the International Olympic Committee said Tuesday.

In a statement, the IOC said it retested 454 samples from the 2008 Beijing Games, using "the very latest scientific analysis methods." The retesting yielded suspicious results from dozens of athletes.

"All those athletes infringing anti-doping rules will be banned from competing at the Olympic Games Rio 2016," the statement from the IOC said.

The IOC said it is expecting 250 more results from retested samples taken at the 2012 London Games.

"The aim is to stop any drugs cheats coming to the Olympic Games in Rio de Janeiro," the IOC said.

Retesting samples from Olympic Games is not a new practice. As drug testing technology improves, the IOC is able to better analyze samples. The Associated Press reports that a few months after the Beijing Olympics, the IOC "reanalyzed nearly 1,000 of the total of 4,000 samples with a new test for the blood-boosting drug CERA. Five athletes were caught, including 1,500-meter gold medalist Rashid Ramzi of Bahrain."

The news service also reports that "nearly 500 doping samples from the 2006 Winter Olympics in Turin" have been retested, but the IOC has not revealed whether any of the tests came back positive. The AP adds: "five athletes were caught in retests of samples from the 2004 Athens Olympics, including men's shot put winner Yuriy Bilonog of Ukraine."

The IOC's Tuesday statement also announced an investigation into the drug testing during the 2014 Winter Games in Sochi, Russia. The scandal surrounding allegations of a massive state-sponsored doping operation in Russia has been gathering strength since the former head of the Russian anti-doping lab, Grigory Rodchenkov, disclosed the details of the illicit enterprise to the The New York Times last week. The newspaper wrote that it was "one of the most elaborate — and successful — doping ploys in sports history." It described the setup, as confessed by Rodchenkov:

"In a dark-of-night operation, Russian antidoping experts and members of the intelligence service surreptitiously replaced urine samples tainted by performance-enhancing drugs with clean urine collected months earlier, somehow breaking into the supposedly tamper-proof bottles that are the standard at international competitions, Dr. Rodchenkov said. For hours each night, they worked in a shadow laboratory lit by a single lamp, passing bottles of urine through a hand-size hole in the wall, to be ready for testing the next day, he said."

The IOC requested the the World Anti-Doping Agency fully investigate the allegations. The IOC also directed its lab in Switzerland — where the Sochi samples will be stored for 10 years — to cooperate with WADA's analysis.

"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," said IOC President Thomas Bach in the statement. "The re-tests from Beijing and London and the measures we are taking following the worrying allegations against the Laboratory in Sochi are another major step to protect the clean athletes irrespective of any sport or any nation."

The revelation about corruption in Russia's anti-doping lab also prompted the U.S. Department of Justice to launch an investigation, according to the Times.

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