By Duncan Mackay in Vancouver

February 17 - Russia's doping problems could ruin the Sochi 2014 Winter Olympics, the vice-president of the International Olympic Committee (IOC) Thomas Bach (pictured left) has warned here.

The reputation of Russian sport has suffered a series of damaging blows following a number of high-profile drugs scandals involving some of its best-known names.

Bach has now told Russia that it must continue its efforts to eradicate the problem before it hosts the Olympics for the first time since Moscow staged the boycotted Summer Games of 1980.

Bach told the international news agency Reuters: "My impression is the Russians have understood and they realise that if they would have a problem with doping, if Russia would be perceived as not fighting against doping as much as other countries, that this would cast a shadow on the Sochi 2014 Games."

Jacques Rogge, the IOC President, revealed on the eve of the opening ceremony here last week that he had spoken to Russian President Dmitry Medvedev about the problem.

Top cross-country skier Alena Sidko, considered a medal contender at the Vancouver Olympics, became the most recent big-name offender just weeks before the start of the Games.

She joined three other leading Russian skiers, triple Olympic champion Julija Tchepalova, 2006 Olympic gold medallist Yevgeny Dementiev and national champion Nina Rysina, who have also been banned.

Russia were also hit by a major scandal on the eve of the Olympics in Beijing in 2008 when they were accused of "systematic doping" by Arne Ljungqvist, the chairman of the IOC's Medical Commission, when seven female athletes were suspended after an analysis of urine samples showed the specimens to be fraudulent.

Bach's warning is particularly significant because he is the favourite to become IOC President when Rogge steps down in 2013 and could be in charge when the Sochi Olympics open.

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