Disciplinary cases have been initiated by the IOC against 28 Russian athletes whose urine samples at the 2014 Winter Olympics in Sochi were allegedly manipulated.
The IOC will reanalyse samples highlighted in the McLaren report, which was produced independently at the request of the World Anti-Doping Agency (WADA) and concluded a state-sponsored doping programme had been in effect in Russia from 2011 to 2015.
A statement on Friday read: "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, as detailed in the IP [McLaren] report earlier in December.
"Prof. McLaren had investigated 95 samples of Russian athletes provided to him by the IOC. They led to the 28 athletes with evidence of sample manipulation.
"They have now been repatriated back to the Lausanne anti-doping laboratory, and re-analysis has already begun on these samples looking for any Adverse Analytical Findings (AAFs)."
The IOC confirmed the samples in question are not currently being treated as positive doping tests, but added: "The manipulation of the samples themselves could lead to an anti-doping rule violation and sanctions."
IOC president Thomas Bach added: "This is the immediate follow-up to Professor McLaren's report. The IOC will go beyond the findings of the IP report by re-analysing all the samples of all the Russian athletes who participated in the Olympic Winter Games Sochi 2014 as well as all those who participated in the Olympic Games London 2012.
"As of now, 27 Russian athletes have already been sanctioned by the IOC as a result of the IOC's own re-analysis programme for the Olympic Games Beijing 2008 and London 2012, which began prior to the Olympic Games Rio 2016, and is still ongoing [for London]. The IOC will also re-analyse all samples from Russian athletes at the Olympic Winter Games Vancouver 2010.
"The protection of clean athletes and the fight against doping are top priorities for the IOC."