A report into claims of state-sponsored doping by Russia at the 2014 Winter Olympics could put the country's place at the 2016 Summer Games in doubt.
An independent commission set up by the World Anti-Doping Agency (Wada) has been investigating the allegations and will publish its findings on Monday.
Any adverse revelations could increase pressure on Russia to be banned from the Rio Olympics entirely.
Its track and field athletes are already barred from the Games.
The 2016 Olympics get under way on 5 August.
The commission looking into Russia's conduct at Sochi is led by Dr Richard McLaren and has been examining claims made by Dr Grigory Rodchenkov.
A former anti-doping chief, Rodchenkov has alleged that dozens of athletes, including at least 15 medallists at the 2014 Winter Olympics, were part of an extensive state-run doping programme.
He has also implicated Russia's security service and the sports ministry.
Russia sports minister Vitaly Mutko has condemned the allegations as "a continuation of the information attack on Russian sport".
BBC sports editor Dan Roan
If ever sport needed its most illustrious event to provide some inspiration, escapism and relief from its various troubles, it is now.
With just three weeks until the start of the Rio Olympics, the focus should be firmly on the squad selections, the venues, the spectacular backdrop that the city will provide, the medal prospects, the glittering opening ceremony and the unique anticipation that usually accompanies the build-up to the Games, the first to be held in South America.
A time to revive cherished memories of London's golden summer of 2012, alongside hopes for new images of national pride.
Instead, at a news conference in Toronto on Monday, the integrity of the Olympic movement will receive one of its most shattering blows when Canadian law professor Richard McLaren reveals the findings of his independent investigation into more lurid allegations of state-sponsored doping in Russia.