New evidence is being used to vet Russian athletes ahead of next month's Pyeongchang Games, the International Olympic Committee said Thursday.
The IOC said a database from the Moscow anti-doping laboratory shows evidence of attempts to "hide and modify" biological data pointing to steroid use. The Olympic body said it will pass on the data to international sports federations, who could take further action.
Russian athletes must compete in neutral uniforms under the Olympic flag in Pyeongchang as part of the country's punishment for what the IOC ruled was a doping program when it hosted the 2014 Sochi Olympics. They will be known as "Olympic Athletes from Russia." An IOC panel led by former French Sports Minister Valerie Fourneyron has been vetting Russian athletes before issuing invitations to compete.
"The (database) was reconstructed by a WADA forensic expert and then subjected to a rigorous authentication process to confirm its accuracy," the IOC said in a statement. "This additional intelligence has been provided to the respective International Federations."
The IOC panel has faced criticism in Russia over a lack of explanation for why some athletes, like six-time Olympic short-track speedskating champion Viktor Ahn, were not invited to Pyeongchang despite not having previously faced doping charges.
The statement released Thursday sheds light on the evidence the panel has used, but it still hasn't confirmed who is in and who is out, or given any individual decisions.
The IOC said that, as well as earlier IOC and World Anti-Doping Agency investigations into Russian doping, it used tipoffs from whistleblowers and sports federations, as well as records of athletes' whereabouts.
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The list of evidence "is comprehensive but by no means exhaustive; and I would like to stress that we also looked at a wide range of intelligence and other sources," Fourneyron said in the statement.
Also Thursday, the IOC said Russian fans will be allowed to fly their flag in Pyeongchang, but organized protests could bring further sanctions.
The IOC said its ban on athletes wearing the Russian tricolor doesn't apply to fans, saying this "cannot be prohibited."
However, it added that "should this appear to be an organized political demonstration the IOC will take this into consideration in its monitoring system."
That could mean Russia won't get to march with its flag at the closing ceremony, which the IOC has offered as an incentive for the country to comply with its rulings.
Russian hockey officials also named a roster for the Olympics, even though IOC vetting is still ongoing.
The team includes former NHL players Pavel Datysuk and Ilya Kovalchuk, each at their fifth Olympics. Former Los Angeles Kings defenseman Slava Voynov, who left the NHL following his arrest on felony domestic violence charges in 2014, is also on the team.
Five Russian players had failed to pass IOC vetting, but officials said only one of the five, former Pittsburgh Penguins winger Sergei Plotnikov, would have made the roster.
Separately, 18 Russians were cleared to compete this year in track and field, including high jump world champion Mariya Lasitskene.