The tactics Russia's government and sports leaders used to help their Olympic athletes get away with doping now have a name: "disappearing positive methodology."

The practice lasted at least four years, covered 28 Olympic sports and the Paralympics and involved at least 312 positive tests that went unreported at the behest of higher-ups in the country's sports ministry, according to a 97-page report issued Monday.

"A mind-blowing level of corruption within both Russian sport and government,'" is what Travis Tygart, the CEO of the U.S. Anti-Doping Agency, called it.

But in his report on Russian doping, arbitrator Richard McLaren did not make any recommendations for the future of the Russian team at the Rio Olympics. He said it was up to others, including the International Olympic Committee, to "absorb and act upon" the report.

IOC President Thomas Bach called the revelations a "shocking and unprecedented attack on the integrity of sports and on the Olympic Games" and said the IOC wouldn't hesitate to apply the toughest sanctions available against those accused of cheating. The IOC executive board will meet Tuesday to begin sorting through options.

McLaren's report said allegations made by Moscow's former anti-doping lab director about sample switching at the Sochi Olympics went much as described in a New York Times story in May. That program involved dark-of-night switching of dirty samples with clean ones; it prevented Russian athletes, including more than a dozen medal winners, from testing positive.

But McLaren said the bottle tampering in Sochi was a one-shot deal. Meanwhile, Russia's "disappearing positive methodology" began in 2011, shortly after Russia's disappointing performance at the Vancouver Olympics. It included the 2013 track world championships in Moscow and was in place as recently as the 2015 swimming world championships in Kazan.

In short, Russia's deputy minister of sports, who was also part of Russia's Olympic Committee, would direct workers at Moscow's anti-doping laboratory of which positive samples to send through and which to hold back. Assisting the plan was Russia's national security service — the FSB, the current version of the Soviet Union's KGB.

McLaren said out of 577 positive sample screenings, 312 positive results were held back — or labeled "Save" by the lab workers — but that was only a "small slice" of the data that could have been examined. More than 240 of the 312 "Saves'" came from track and field and wrestling, but other sports involved included swimming, rowing, snowboarding — and even table tennis.

McLaren suggested the numbers could have been higher, but he had only 57 days for his investigation, which was commissioned by the World Anti-Doping Agency after the Times story came out.

Time is crucial because the Olympics begin Aug. 5, and decisions about Russia's participation in Rio must be made.

The U.S. Anti-Doping Agency is one of several sports organizations that said it would call for a full ban of the Russian team if the report showed evidence of a widespread, state-sponsored doping conspiracy. McLaren's report said it did, and the investigator said he was "unwaveringly confident in my report."

He insisted there was no leak of his report, as several sports organizations suggested over the weekend, when draft letters calling for Russia's ban were leaked to the media.

U.S. Olympic Committee CEO Scott Blackmun said the report proved a point he'd made earlier this summer.

"The current anti-doping system is broken and urgently requires the attention of everyone interested in protecting clean athletes,'" he said.

He was relying on the IOC and international sports federations to figure out appropriate sanctions. But there is far from a consensus on what those sanctions will be, as the sports world toes the line between what Bach called "collective responsibility and individual justice."

Among those not in favor of a full Russian ban was the head of gymnastics — a sport that was not among the 28 with non-reported positives.

"The right to participate at the games cannot be stolen from an athlete, who has duly qualified and has not be found guilty of doping," said Bruno Grandi, president of gymnastics' international federation. "Blanket bans have never been and will never be just."

Reporting by
EDDIE PELLS, AP National Writer