(Adds WADA reaction)
By Brian Homewood
ZURICH, Feb 1 (Reuters) - Twenty-eight Russian athletes have had their Olympic doping bans overturned and results from the 2014 Winter Games in Sochi reinstated after their appeals were upheld by sport's highest tribunal on Thursday.
The Court of Arbitration for Sport (CAS) said there was insufficient evidence of anti-doping violations against the athletes, but the International Olympic Committee (IOC) said they would not necessarily be invited to the Pyeongchang Games this month.
Eleven other athletes were confirmed to have committed doping offences although CAS said it had reduced their lifetime Olympic bans to a suspension from this year's Games.
The original bans were imposed by the IOC following an investigation into alleged systematic doping at the Sochi Games which Russia hosted four years ago.
The IOC has also banned Russia from Pyeongchang as a result of its "unprecedented systematic manipulation" of the anti-doping system, although individual Russian athletes can compete as neutrals if they can meet stringent IOC criteria. Russia has repeatedly denied state involvement in doping.
Russian President Vladimir Putin welcomed the CAS ruling.
"This, of course, cannot but give us joy," he told reporters. "It confirms our position on the fact that the vast majority of our athletes are clean."
Putin added that Russia still needed to continue its fight against doping along with the World Anti-Doping Agency (WADA).
"We will do this in determined fashion," he said.
Russian sports minister Pavel Kolobkov said the IOC would be asked to allow the 28 athletes to compete in Pyeongchang.
"We really hope that the IOC make a decision in favour of all clean athletes who earned the right to compete at the Olympics," he told reporters.
But the IOC, which has cleared 169 Russians to compete, said that "not being sanctioned does not automatically confer the privilege of an invitation".
The IOC said the confirmation of 11 cases "clearly demonstrates once more the existence of the systemic manipulation of the anti-doping system" in Sochi.
It regretted that the "proven" existence of the systemic manipulation was not considered for the other cases.
"This may have a serious impact on the future fight against doping," the IOC said.
CAS said its role was "not to determine generally whether there was an organised scheme allowing the manipulation of doping control samples" but was limited to dealing with the individual cases.
WADA said it noted "with serious concern" the decision by CAS, given that "all 39 athletes were part of Russia's systematic doping program".
"WADA understands that this decision will cause dismay and frustration among athletes. The Agency supports the IOC's intention to analyse these decisions very carefully and consider all options, including an appeal to the Swiss Federal Tribunal," the statement added.
Cross-country skier Alexander Legkov, who won gold in the 50km and silver in 4x10km, and Alexander Tretyakov, who won gold in the men’s individual skeleton, were among those to be cleared.
Alexander Zubkov, president of the Russian bobsleigh federation, was one of the 11 whose doping offences were confirmed and he remained stripped of his two gold medals.
"I have said many times that I have never doped and do not dope now," he told Reuters. "What am I being accused of? What anti-doping rule violation do they want to slap against me?"
Jim Walden, lawyer for Russia’s former anti-doping chief-turned whistleblower Grigory Rodchenkov, said the ruling provided "a very small measure of punishment for some athletes but a complete 'get out of jail free card' for most".
The United States Anti-Doping Agency said the IOC should have dealt with the matter earlier.
"Slamming dozens of cases through the process on the eve of the Olympic Games has not served justice and as such the integrity of the Games has been sabotaged," its chief executive Travis Tygart said.
"The whole mess truly stinks and the nightmare continues for clean athletes." (Additional reporting by Karolos Grohmann in Berlin, Gabrielle Tetrault-Farber, Denis Pinchuk and Christian Radnedge; Editing by Mitch Phillips and Ed Osmond)