The International Olympic Committee has banned Russia from the 2018 Winter Olympics because of an alleged state-supported doping program.

But the committee says Russian athletes who can prove they have not used performance-enhancing drugs may compete under Olympic flag.

The committee had heard from all sides in the run-up to what may end up being one of its most important decisions ever on doping in the premier sports event.

Investigations and drug tests by the World Anti-Doping Agency (WADA) and testimony by several whistle-blowers has led to dozens of Russian athletes being banned for doping, as well as allegations that Russian officials ran a covert doping operation for its Olympic athletes from 2012 to 2015, peaking at the Sochi Olympics in 2014.

Russian officials deny any state involvement in the doping of athletes.

While other nations' Olympics teams had questioned whether Russia should be allowed to participate, Russian Deputy Prime Minister Vitaly Mutko made a last-minute appeal to the committee, saying, "We are relying on common sense, on the IOC Charter, on the assumption that no one abolished the presumption of innocence."

The IOC has not in the past imposed a total ban for doping, instead passing the decision on individual athletes to the international federations governing each individual sport.

Explainer: The IOC Ruling And Russia's Fate At The Winter Olympics

With the exception of one athlete, Russia was barred from track-and-field events and weightlifting at the 2016 Summer Olympics in Rio de Janeiro, but it was allowed to field teams in other sports.

The IOC, however, is taking a stronger approach to the Winter Olympics, given that the most serious allegations against Russia relate to its hosting of the 2014 Winter Games in Sochi.

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