Sochi: Former director general of Russia's anti-doping agency Ramil Khabriev has admitted that his country has "a serious problem" in doping, adding that 40 per cent of its drug-test violations have come in youth sports.

Russia was suspended from international athletics over doping, and must reform in order to return for the Olympics. Recently, four Russian weightlifters were suspended after failing drugs tests at the World Championships.

"In Russia, the doping issue is acute, we can't deny it," Khabriev, who left his post at Russian Anti-Doping Agency (RUSADA) earlier this month, was quoted as saying by BBC on Sunday.

"We have the most violations in anti-doping rules in comparison with other countries. This, of course, shows there's a serious problem. Around 40 percent of these violations are from youth sports, which is alarming."

The IAAF voted to suspend Russia's athletics federation in November.