Russia could lose medals from the 2008 Beijing Olympics after 14 of its athletes tested positive for banned substances during re-tests conducted from eight-year-old samples, the Russian Olympic Committee (ROC) said on Tuesday.
The latest positive tests are a further blow to Russia, whose track and field athletes have been suspended since November, and its hopes of sending a full team to the Rio Olympics in August.
In a bid to improve their chances of returning to competition in time for the Games, Russia's athletics federation said on Tuesday it would not include any athletes on its Olympic team, who had been banned for doping in the past.
Russian media reported a list of athletes, including several Beijing medal winners, who had tested positive, although Russian Olympic officials won't formally name the athletes until after their B samples are tested next month.
Those named by the media include high jumper Anna Chicherova, who won a bronze medal in Beijing and went on to claim gold in London in 2012.
Her coach confirmed she was on the list.
"Three days ago Anna received a notice that her doping sample from the Beijing Olympics tested positive after a re-check and she called me," Chicherova's coach Yevgeny Zagorulko told Russian media.
"So far, this is at the development stage and this has not yet been finally confirmed. But all are aware of this and are dealing with the issue," he said.
The IOC are expected to announce the results of re-tests of 250 samples from the London 2012 Games this week. Samples from the Sochi 2014 Winter Olympics are also being retested.
Russia's Sports Ministry said cheats would be punished.
"The Ministry of Sport is extremely disappointed to hear the speculation that Russian athletes are among those found to have violated anti-doping rules at the 2008 Beijing Olympics after re-testing their samples," it said in a statement.
"Any athletes found cheating should face corresponding sanctions. We have taken numerous steps to eradicate the issue of doping, and understand that the roots of the problem, particularly in athletics, go back to the past."
The country's track and field athletes have been suspended since November after an international investigation uncovered damning evidence of doping and corruption.
World athletics' governing body, the IAAF, will decide on June 17 whether Moscow has done enough to clean up its act and be readmitted to competition.
