Russia could face a complete Olympic ban if allegations of state-sponsored doping at the 2014 Sochi Winter Olympics are proven on Monday.
An independent commission set up by the World Anti-Doping Agency (Wada) has been investigating the claims and is to publish its findings.
Russian track and field athletes are banned from international competition,including the Rio Olympics.
But individual athletes can compete as neutrals if they prove they are clean.
Russia are currently challenging the ban on their athletes at the Court of Arbitration for Sport (Cas), with the tribunal expected to conclude on 21 July.
However, Monday’s findings may put more pressure on the nation if there are any adverse revelations.
The commission, headed by Dr Richard McLaren, has primarily been looking into claims made by Dr Grigory Rodchenkov, a former anti-doping chief, who alleged dozens of athletes, including at least 15 medallists at the 2014 Winter Olympics, were part of an extensive state-run doping programme.
Rodchenkov described a massive, tightly organised doping operation involving Russia’s security service and the sports ministry.
But Sports Minister Vitaly Mutko condemned the allegations as “a continuation of the information attack on Russian sport”.
The Russian weightlifting team are also facing the prospect of a ban from Rio after repeated anti-doping violations.
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, on Monday, at a news conference in Toronto, the integrity of the Olympic movement will receive one of the most shattering blows in its history when Canadian law professor Richard McLaren reveals the findings of his independent investigation into more lurid allegations of state-sponsored doping in Russia.