70 percent of Russian athletes cleared to compete at Rio 2016

The Court of Arbitration for Sport has ruled the Olympic committee's blanket ban of any athlete with a past doping sanction is "unenforceable," Reuters reports.

Based on the ruling, the IOC decided to allow 271 of 389 Russian athletes to compete in Rio, including 31 of 35 swimmers during the game's first week.

The CAS ruled on the IOC's attempt to bar Russian athletes with a prior doping ban, citing that the rule "does not respect the athletes' right of natural justice."

Russian rowers Anastasia Karabelshivo and Ivan Podshivalov were appealing the decision in an effort to force the IOC to allow their inclusion at Rio 2016, but the CAS determined their participation would be up to the rowing federation.

The attempted blanket ban of Russian athletes with a history of doping would go against the IOC's stated goal to "provide the athletes with an opportunity to rebut the presumption of guilt and to recognize the right to natural justice," the CAS concluded.

Russia has been mired in controversy after evidence of state-sponsored doping was uncovered, leading to an attempt by the IOC to ban athletes with previous PED busts after it was decided they would not completely ban the entire country from Rio.