IOC investigate 28 Russian athletes over allegedly manipulating drug tests during Sochi Winter Olympics
The International Olympic Committee has opened disciplinary proceedings against 28 Russian athletes who competed at the Winter Olympics in Sochi.
Evidence emerged in the McLaren report published earlier this month of manipulation of one or more of the athletes' urine tests during the 2014 Games.
An IOC statement read: "At this point in time, these 28 new cases are not AAFs (adverse analytical findings), like a positive doping test. However, the manipulation of the samples themselves could lead to an anti-doping rule violation and sanctions."
Professor Richard McLaren found evidence that over 1,000 Russian athletes in more than 30 Olympic and Paralympic sports were involved in a doping conspiracy that began at least as early as 2011 and ran until 2015.
McLaren's interim report in July led to Russian athletes being banned from several events at the Rio Olympics, including athletics, and from the whole of the Paralympics.
In his final report, he detailed evidence of 12 medal-winning competitors from Sochi being implicated.
He was given 95 samples of Russian athletes by the IOC, leading to these 28 being identified. Re-analysis of the samples has begun at the Lausanne Anti-Doping Laboratory.
IOC president Thomas Bach said: "This is the immediate follow-up to Professor McLaren's report. The IOC will go beyond the findings of the 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."
Twenty-seven Russian athletes have already been sanctioned following re-analysis of samples from the summer Olympic Games in Beijing and London.
The IOC will also re-analyse all samples from Russian athletes given at the Winter Games in Vancouver in 2010.