The International Olympic Committee (IOC) announced Friday that it will reanalyse all 254 urine samples taken from Russian athletes who took part in the 2014 Sochi Winter Olympics.
The IOC said it had also extended the mandate of its own Oswald disciplinary commission to examine all samples collected from Russian athletes during the London Summer Olympics in 2012.
The decisions were taken, the IOC said, following the publication Friday of Richard McLaren's full report into doping in Russia that revealed an "institutional conspiracy" by Moscow to cheat between 2011-15.
All 63 blood samples collected from Russian athletes in Sochi have already been reanalysed by the IOC in cooperation with McLaren. All came back negative.
The IOC said the urine samples would be retested because "McLaren's mandate did not include a full reanalysis of all these samples".
Turning to the London Games, the IOC said reanalysis of some of the Russian samples was already under way following intelligence provided by McLaren to the IOC.
Eleven Russian athletes have already been sanctioned by the IOC as a result of the IOC's own re-analysis programme, which began prior to the Rio Olympics and is ongoing.
The Lausanne-based IOC added its thanks to McLaren and his team, saying his report showed that there "was a fundamental attack on the integrity of the Olympic Games and one sport in general".