Doping bans on 28 Russian athletes were overturned on Thursday, throwing the International Olympic Committee's policy on Russia doping into chaos just over a week before the start of the Winter Games in South Korea.
The Court of Arbitration for Sport (CAS) upheld the appeals of athletes given lifetime Olympic bans for doping violations at the 2014 Sochi Winter Games, saying there was insufficient evidence to show they had broken the rules.
The ruling means that their 2014 results are reinstated and they could now seek to participate in the Winter Games in Pyeongchang, which open on February 9.
In a further 11 cases, CAS ruled that doping violations had been committed but that lifetime bans were not justified and the punishments were cut to a ban for the 2018 Games alone.
Among the reinstated athletes were cross-country ski gold medalist Alexander Legkov and skeleton gold medalist Alexander Tretiakov.
It was not immediately clear if any of the 28 would seek to take part in Pyeonchang. To be eligible to compete in South Korea, they would need to be cleared by the IOC Invitation Review Panel and subsequently selected to join the team of 169 Russian athletes competing as neutrals.
The Kremlin said it was "very happy" with the decision. "This information about the CAS decision regarding our athletes confirms that active efforts to protect their rights in courts and in other ways are justified, they can be effective and they must continue," Kremlin spokesman Dmitry Peskov said on a conference call with journalists.
The 39 athletes whose appeals were considered by the IOC on Thursday were given lifetime Olympic bans in December, after an independent report commissioned by the IOC into doping by Russian athletes at the 2014 Games.
The IOC banned the entire Russian team from the 2018 Games for a "systemic manipulation" of anti-doping rules. Russia denies the charge.
The World Olympic body said Russian athletes who can prove that they are clean would be "invited" to take part in Pyeongchang, under neutral flag. They would compete as "Olympic Athletes from Russia" -- with no use of the Russian flag or national anthem permitted.
The ban on Russia's involvement in the 2018 Games is the severest punishment ever meted out by the IOC on a participating nation, let alone a powerhouse of the Olympic movement.
Russia's Olympic Committee was also ordered to pay $15 million to reimburse the IOC's costs of investigating the doping scandal and help set up the new Independent Testing Authority (ITA).
Russia's suspended Paralympic Committee, which has also been banned from the Paralympic Winter Games, which follow the Olympics in Pyeongchang, is also due to hold a news conference in Moscow Thursday.