Russia's Olympic Committee said on May 24 that it had been informed by the International Olympic Committee that retests of samples from the 2008 Olympics in Beijing showed positive results for 14 Russian athletes.
The 14 Russian athletes had competed in three different sports during the 2008 Olympics.
The Russian committee said in a statement that it would not release the names of the Russian athletes until it receives the results of follow up tests on B-samples and official disciplinary proceedings begin.
But the TASS news agency reported that most of the Russian athletes were involved in track and field events.
TASS also quoted the coach of Olympic high-jump champion Anna Chicherova as saying that she was among those who tested positive for illegal performance-enhancing drugs.
Chicherova won a bronze medal at the 2008 Olympics and won gold in London at the 2012 Olympics.
Thomas Bach, the head of the International Olympics Committee, has suggested that Russia could be barred from the 2016 Olympics in Brazil if allegations of state-sponsored doping are confirmed.