The president of the International Olympic Committee (IOC) expressed concern over doping cases involving Russian athletes.

"We have indeed been concerned by the number of positive cases," Jacques Rogge told journalists days before the start of the Olympic Games in Vancouver.

"I had a meeting with [Russian] Sport Minister Vitaly Mutko. I alerted him and he said he would do everything to improve the situation. I also had a meeting with the president of Russia, Mr. Medvedev, and insisted on strong action on doping. He promised he would launch that," Rogge said.

Russian female skier Alyona Sidko's was recently disqualified over doping-use charges.

The Russian ski federation disqualified Sidko, the 2006 Olympic bronze medalist, for two years and excluded her from the national Olympic team after she tested positive for the use of doping at a Russian skiing competition last month.

Russian athletes have been recently plagued by doping-related cases and subsequent disqualifications. Last month, the International Ski Federation (FIS) alone disqualified two Russian female skiers, Yulia Chepalova and Natalia Matveyeva, on accusations of doping use.

Before the opening of the 2008 Olympics in China, seven Russian female athletes were disqualified from the Games after they were ruled to have switched urine samples before tests for performance-enhancing drugs.

The problem of performance-enhancing drugs was raised at the state level by Russian Prime Minister Vladimir Putin last February, who urged tougher penalties for those athletes using drugs and proposed establishing a state doping control system.

But a leader of Russia's national anti-doping agency RusADA said earlier there will be no doping-related scandals at the February 12-28 Winter Olympic Games.

"We can say with full conviction: we have done all that depends on us for all Russian athletes to leave for Vancouver checked and 'clean,'" Alexander Derevoyedov said last week.

VANCOUVER, February 9 (RIA Novosti)