So far only one of the Russian athletes stripped of Olympic medals for doping has given it back to the International Olympic Committee, a senior Moscow sports official said Monday.

Runner Anton Kokorin, who won bronze in Beijing in the men's 4X400m relay team, is the only athlete to have returned his Olympic medal, Yelena Ikonnikova, the anti-doping coordinator of the athletics federation (RusAF), told AFP.

The IOC has ruled that all the athletes who were stripped of their medals over doping violations must give them back.

Ikonnikova confirmed that Russia's athletics federation has received a list of the athletes concerned and passed it on.

"We've distributed the list and the IOC demand for the return of Olympic medals to all the athletes and the regional (athletics) federations concerned," she said.

Ikonnikova added that RusAF has served as a mediator between the Russian Olympic Committee and the international one and the athletes.

Last week Russian Olympic Committee chief Alexander Zhukov said that it "was continuing with its work" to return the medals.

"Although only few athletes have agreed to return medals, we are continuing to work on this. We are contacting them via their sports federations," he told TASS agency.

Aleksandra Brilliantova, the ROC legal department chief, complained however that the ROC had no leverage to force the country's athletes to return their Olympic medals.

"The ROC doesn't have any established procedure for returning medals, and this is a serious problem," TASS agency quoted Brilliantova as saying.

Media reports said that 13 Russian athletes who won medals at the 2008 Beijing Games and eight who were medal winners at London in 2012 have tested positive for banned substances and have been ordered to return their gongs to the IOC.

Some of the doping violators have already retired and are seeking to defy the order and hold onto their Olympic medals, causing additional friction between the IOC and the ROC.

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