A new report by the World Anti-Doping Agency (WADA) on alleged drug use in Russian sports has found evidence that more than 1,000 Russian athletes were involved in or benefited from manipulations of their positive drug tests.
The report released in London on December 9 follows up on a landmark report last summer that resulted in bans on dozens of Russian athletes, preventing them from participating in the Olympic Games in Rio de Janeiro.
The new report documents what Canadian lawyer Richard McLaren, who authored both WADA reports, says was "a cover-up that dates back until at least 2011 and continued after the Sochi Olympic Games" in February 2014.
"It was a cover-up that evolved over the years from uncontrolled chaos to an institutionalized and disciplined medal-winning strategy and conspiracy; a cover-up that operated on an unprecedented scale," McLaren told a news conference.
"We have evidence revealing that more than 500 positive results were reported as negative, including well-known and elite-level athletes, who had their positive results automatically falsified," he said.
Russian officials have denied there was an organized doping program, saying they are working with WADA to bolster its drug controls.
After the December 9 announcements, former Olympic judo champion Dmitry Nosov, who is now a deputy in Russia's lower house of parliament, said the report was "a political strike" aimed at Russia in retaliation for "the situation with [the annexed Ukrainian region of] Crimea, Ukraine, and Syria."
The Russian Sports Ministry, in a statement, said it would examine the WADA report before commenting in detail but insisted that there was no "state program of support for doping [in] sports" and said it "continues to fight doping with a position of zero tolerance."
The Kremlin also said it would study the report, while Russian athletics chief Dmitry Shlyakhtin declined to comment, saying he had not seen it.
Russia's anti-doping agency, RUSADA, has asked WADA to provide it with its evidence.
"Despite the presented accusations I would like to point out that there has never been an organized system in Russia for the falsification [of doping samples]," said Vitaly Smirnov, the head of Russia's independent anti-doping commission, IPADC.
"From now on we will not tolerate their allegations starting with 'all of you' and 'you have a state-backed program,'" RUSADA official and former pole-vaulting champion Yelena Isinbayeva told Russian state television. "I doubt very much, though, that if asked to present specific proof of guilt, they will be able to do so."
The International Olympic Committee (IOC), in a statement, said that it will retest more than 250 doping samples from Russian athletes at the 2014 Sochi Winter Games and examine all Russian samples from the 2012 London Olympics.
The IOC said the findings in the new report "show that there was a fundamental attack on the integrity of the Olympic Games and on sport in general."
The IOC has two separate commissions that will study McLaren's findings and prepare "the appropriate sanctions and measures," the statement added.
Corruption On 'Unprecedented Scale'
The new WADA report found evidence that the urine samples of 12 Russian medalists -- including four gold-medal winners -- from the 2014 Winter Olympics in Sochi were tampered with.
In all, it describes a "conspiracy" involving more than 30 sports that began in 2011 and spanned the 2012 Olympics in London, the 2013 World Athletics Championships, and the Sochi Games. The report says the cover-up continued "at least until 2015" and also involved Paralympic sports.
"These athletes were not acting individually but within an organized infrastructure," McLaren said. McLaren added that he was leaving it up to individual athletic federations to determine whether to release the names of the athletes who allegedly benefited from the cheating.
Speaking specifically about the 2012 London Olympic Games, McLaren said "the Russian team corrupted [them] on an unprecedented scale, the extent of which will probably never be fully established."
The conclusions of the initial McLaren report were fully confirmed by the latest findings, he said.
McLaren said there was no "direct evidence" that former Russian Sports Minister Vitaly Mutko knew about the doping program. He also said there was no evidence that members of the Russian Olympic Committee were aware of it.
McLaren said Russia's anti-doping agency had moved "in the right direction" in recent months, but called on Moscow to change its "culture" of cheating.
Clemens Prokop, chairman of Germany's athletics federation, called for Russia to be excluded "from all international championships and Olympic Games until there is a credible change."
Andrea Gotzmann, head of Germany's anti-doping agency, likewise called for "consequences" for all involved.
"The details of systematic, organized, and perfidious doping in Russian sport are staggering," she told the dpa news agency.
The investigation into the alleged Russian doping was initiated by revelations by Russian track-and-field athlete Yulia Stepanova and her husband, Vitaly, a former Russian anti-doping official. In an interview with the BBC on December 9, Stepanova said she and her family had been in hiding for the last two years, fearing for their lives.
She described how her coach convinced her to begin using illegal substances when she was 20 by telling her "it's normal; it's what all athletes do."
With reporting by Reuters, dpa, the BBC, and TASS