An international anti-doping commission has recommended that Russia's Athletics Federation be banned from international competition over widespread doping offences - a move that could see the powerhouse Russian team excluded from next year's Rio Olympics.
Russian Sports Minister, Vitlay Mutko, said there was no evidence for the accusations against the Federation.
The commission, set up by the World Anti-Doping Agency (WADA), found however a "deeply rooted culture of cheating" in Russian athletics. But it also identified what it called systemic failures in the global governing body, the International Association of Athletics Federations (IAAF).
"These are dark days," said IAAF President Sebastian Coe after publication of the long-awaited report. He gave Russia until the end of the week to respond to the accusations.
Dick Pound, former WADA President and head of the commission that produced the report, referred to an unprecedented corruption scandal now shaking soccer's governing body, FIFA.
"I hope all sports will look at their governance and their anti-doping systems because their existence may be at risk," he told a news conference. "public opinion is going to move towards the view that all sport is corrupt."
The scandal revolves around accusations that officials demanded money from top athletes, with the connivance of coaches, to 'bury' medical tests from Russian athletes that showed drug use to enhance performance.
The commission said in its report that the London 2012 Olympics had been "sabotaged" by the widespread inaction of international and national anti-doping authorities.
Russia finished second behind the United States in the medal table at the 2012 Olympics, with 17 medals, eight of them gold, and has long been one of the chief players in track and field.
A decision to suspend Russia could be taken only by the IAAF.