Russia has dismissed claims from the former head of its doping laboratory that he organised a sophisticated cheating programme at the 2014 Winter Olympics.
The Kremlin branded Grigory Rodchenkov a "traitor" and said his allegations about widespread doping of Russian medal winners at the Sochi Games were "treacherous slander".
Rodchenkov told The New York Times dozens of Russian competitors - including at least 15 medal winners - were part of a state-run doping programme which was carefully planned to ensure the host nation's dominance at the Games.
Rodchenkov - who fled Russia for Los Angeles fearing for his safety after widespread Russian doping was exposed by the World Anti-Doping Agency (WADA) - told how he created a three-drug cocktail of banned substances, which he mixed with alcohol for the athletes.
He also claimed he worked with members of Russia's secret services in the dead of night to replace tainted urine samples with clean ones during the Games.
Rodchenkov estimated that as many as 100 dirty samples were successfully covered up at the event - where Russia finished ahead of the United States at the top of the medals table.
The allegations complicate Russia's efforts to distance itself from previous accusations of state-sponsored doping made by an independent WADA commission and are likely to make it harder for Moscow to overturn a ban on its athletes competing at the Rio Olympics.
Russian Deputy Sports Minister Yuri Nagorny leaves a news conference in Moscow, Russia, Friday, May 13, 2016. Two Olympic gold medalists from Russia denied doping Friday, a day after they were named in a newspaper report detailing state-sponsored cheating at the 2014 Sochi Games. Bobsled champion Alexander Zubkov and cross-country skier Alexander Legkov were among the athletes accused in a New York Times article of doping by the former head of the Russian national drug-testing laboratory. (AP Photo/Alexander Zemlianichenko)
"These allegations look absolutely groundless," Dmitry Peskov, a Kremlin spokesman, told reporters in a conference call on Friday. "They are not substantiated by any trustworthy data, they are not backed by any sort of documents. All this simply looks like slander by a turncoat."
Asked about the prospects of Russian track and field athletes being allowed to compete in Rio, Peskov said: "We hope everything will be fine."
Two of the sportsmen named in the New York Times report, cross-country skier Alexander Legkov and bobsledder Alexander Zubkov, have rejected the allegations against them as "nonsense and slanderous".
"We need to take legal action against these people," Legkov told Russia's Match TV. "All of it (the allegations) is not serious, it is complete rubbish and we need to stop it.
The sportsman, who won a gold and silver medal in the Sochi games, added: "I performed honestly. My Olympic victory was not accidental."
Zubkov was equally dismissive of the allegations in comments to the same channel.
"It is all nonsense and slander directed at Russian sportsmen, who took part in the Olympics. It is unacceptable."
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