The IOC said the action was being taken following evidence produced by World Anti-Doping Agency investigator Richard McLaren, who released his latest report on December 9.

McLaren has accused Russia of “state sponsored” doping, using the intelligence services to organise the swapping of samples at Sochi.

“The IOC is initiating disciplinary cases against all 28 athletes for whom there is evidence of manipulation of one or more of their urine samples that were collected at the Olympic Winter Games Sochi 2014,” an IOC statement said.

McLaren found that 28 of the 95 samples his team studied had signs of “manipulation”, said the IOC.

The 28 samples are now being re-analysed at the Lausanne Anti-Doping Laboratory. The Olympic body said the cases are not yet doping failures but that the tampering alone could lead to sanctions.

IOC president Thomas Bach said experts would now re-analyse all samples from Russian athletes at the Sochi Winter Olympics and the London Olympics in 2012.

Twenty-seven Russian athletes have already been sanctioned by the IOC as a result of re-testing of some samples from the 2008 Beijing Games and London. All Russian samples from the 2010 Vancouver Winter Games are also to be re-tested.

The Russian government has denied any official involvement in the doping. But former sports minister and current Deputy Prime Minister Vitaly Mutko was banned from attending the Rio Olympics this year because of the controversy.

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