FILE PHOTO: Alexander Tretyakov of Russia reacts after winning the men's skeleton competition at the Bobsleigh and Skeleton World Championships 2013 in the Swiss mountain resort of St. Moritz February 2, 2013. REUTERS/Arnd Wiegmann

MOSCOW (Reuters) - Four Russian skeleton athletes, including Olympic champion Alexander Tretyakov, have been banned for life from the Olympics after being found guilty of doping at the 2014 Sochi Games, the International Olympic Committee (IOC) said on Wednesday.

Tretyakov, Sochi bronze-medal winner Elena Nikitina, Maria Orlova and Olga Potylitsyna have been “found to have committed anti-doping rule violations,” the IOC said in a statement.

“The four athletes are declared ineligible to be accredited in any capacity for all editions of the Games of the Olympiad and the Olympic Winter Games subsequent to the Olympic Winter Games Sochi 2014,” the IOC said.

The IOC added it had disqualified the athletes from Sochi, effectively stripping Tretyakov and Nikitina of their Olympic medals. Orlova and Potylitsyna did not win medals in Sochi.

The IOC did not disclose the nature of the doping violations.

Earlier this month, the IOC banned six cross-country skiers from the Olympics for violating anti-doping rules as part of an investigation into allegations of widespread doping among Russians and sample tampering by laboratory and security officials at the Sochi Games.

The IOC has been re-testing all Russian athletes’ samples from the 2014 Games following revelations by Grigory Rodchenkov, the former head of Moscow’s suspended anti-doping laboratory, of a scheme to cover up home competitors’ positive samples.

The IOC is set to decide next month on the participation of Russian competitors at the Pyeongchang winter Olympics in South Korea in February.