A letter drafted by U.S. and Canadian anti-doping leaders is urging Russia's removal from the upcoming Olympics.
This comes before the public release of a report Monday by Western University law professor Richard McLaren.
It is expected to detail a state-sponsored doping system that corrupted the country's entire sports program.
The letter, obtained by Reuters, encourages exceptions for Russia-born athletes who can prove they were subject to strong anti-doping systems in other countries.
USADA CEO Travis Tygart said the letter, which has backing from anti-doping agencies in at least six countries and athlete groups from around the world, was drafted with no intent for it to become public unless the McLaren report contains evidence of a major state-sponsored doping program.
The McLaren report was sparked by a New York Times story accusing the Russian government of helping to manipulate tests at the Sochi Games to ensure cheaters wouldn't get caught.
Preliminary findings from the report, released last month, found "mandatory state-directed manipulation of laboratory analytical results operating within" the Moscow anti-doping lab from at least 2011 through the summer of 2013. Those findings also said Russia's "Ministry of Sport advised the laboratory which of its adverse findings it could report to WADA, and which it had to cover up."
Based in part on that information, the letter to the IOC anticipates that the McLaren report will show the Russian government helped organize a "systematic undermining of the drug testing of Russian athletes for many years in a successful effort to cheat to win.
