In his report, WADA's Richard McLaren accused Russia of "state-sponsored" cheating that involved more than 1,000 athletes across more than 30 sports.
A new report into systematic Russian doping details a wide-ranging "institutional conspiracy" that involved more than 1,000 athletes across more than 30 sports, including evidence corroborating large-scale sample swapping at the 2014 Sochi Winter Olympics.
World Anti-Doping Agency investigator Richard McLaren said Friday the conspiracy involved the Russian Sports Ministry, national anti-doping agency and the FSB intelligence service, providing further of state involvement in a massive program of cheating and cover-ups.
"It is impossible to know just how deep and how far back this conspiracy goes," McLaren said at a news conference in London.
"For years, international sports competitions have unknowingly been hijacked by Russians. Coaches and athletes have been playing on an uneven field. Sports fans and spectators have been deceived. It's time that this stops."
But the Russian Sports ministry denied any state-run doping programme.
Responding to the report on Friday, the ministry said in a statement, "The Russian Sports Ministry with full responsibility states there are no government programmes to support doping in sport," the ministry said in a statement, adding that it "will continue the fight against doping with zero tolerance."
The ministry said it would carefully study the report and would fully cooperate with anti-doping bodies.
McLaren said his conclusions were based on irrefutable forensic evidence, including DNA analysis proving that samples were swapped and other tests showing that doping bottles were opened.
McLaren accused Russia of "state-sponsored" cheating and said salt and coffee was used to manipulate samples when checked by international experts at the Sochi Winter Olympics in 2014.
"The Russian Olympic team had corrupted the London Games on an unprecedented scale," added McLaren.
TRT World correspondents Samantha Johnson and Daria Bondharchuk give more details on this story from Istanbul and Moscow.
McLaren's latest report will put pressure on the International Olympic Committee (IOC) to take action ahead of the 2018 Winter Games in Pyeongchang, South Korea.
His findings will be sent to the IOC, which has two commissions looking into the allegations.
IOC President Thomas Bach has said stiff sanctions will be taken against any athletes and officials implicated in doping.
He said he favours lifetime Olympic bans for anyone involved.