A potentially damaging new report finds dozens of Russian athletes at the 2014 Winter Olympics in Sochi – including gold medalists – took part in a secret state-run doping program.

The former director of Russia’s antidoping lab, Grigory Rodchenkov, told The New York Times he helped develop drug cocktails for athletes containing a mixture of banned substances and alcohol.

In order to fool drug tests, he and other Russian antidoping and intelligence experts opened bottles that were believed to be tamper-proof, swapping out drug-laden urine samples with clean ones collected months before the games, Rodchenkov adds.

The scheme involved top Russian Olympians, including 14 members of the cross-country ski team, Rodchenkov said. None of the athletes were ever punished, and Russia went on to win the most medals at Sochi, beating out the United States.

“People are celebrating Olympic champion winners, but we are sitting crazy and replacing their urine,” Rodchenkov told the New York Times.

Russia’s sports minister denied the allegations, calling Rodchenkov’s report “a continuation of the information attack on Russian sport.”

The IOC responded by saying it "would not hesitate" to retest drug samples from the 2014 Winter Games in Sochi if there was evidence that doping controls were manipulated, according to the Olympic body's medical director.

"The IOC will follow up any issues very carefully," medical director Dr. Richard Budgett told The Associated Press. "We did have international experts in the lab monitoring all the testing going on. We made it as secure as we could."

Budgett said the International Olympic Committee stored all doping samples from Sochi at its lab in Lausanne, Switzerland. The IOC retains Olympic samples for 10 years to allow for reanalysis with improved testing methods.

"We will consider whether reanalysis will help us ascertain if there was any manipulation or not," Budgett said in a telephone interview. "There is no decision on that yet. But if there is evidence of manipulation, we would not hesitate to test."

Normally, the IOC prefers to wait until near the end of the 10-year statute of limitations because it can use the very latest testing techniques, but the Sochi allegations could lead to earlier reanalysis.

The World Anti-Doping Agency announced Tuesday it was expanding its investigation into doping inside Russian sports. The move came two days after Vitaly Stepanov told "60 Minutes" that he had conversations with the former director of the Moscow anti-doping lab, who told him there was a "Sochi List" that included four champions from the 2014 Games. They were not identified.

Stepanov said the former lab director, Grigory Rodchenkov, told him that agents from Russia's Federal Security Service (FSB) acted as doping control officers during the Olympics, which severely compromised the lab's integrity.

WADA President Craig Reedie said the claims "offer real cause for concern, as they contain new allegations regarding attempts to subvert the anti-doping process at the Sochi Games."

WADA had a team of observers in Sochi monitoring the entire doping control process.

Natalya Zhelanova, the anti-doping adviser to Russia's sports minister, said the ministry would cooperate with any WADA investigation.

Budgett, meanwhile, said he had no information to report on the results of retesting of hundreds of samples from the Beijing and London Olympics. The IOC began retesting samples recently to weed out any drug cheats before they compete at the Rio de Janeiro Games in August.

"The process is still ongoing," Budgett said.

Any positive findings could result in retroactive disqualifications and stripping of medals.

The Associated Press contributed to this report.