It was revealed earlier this week that three unnamed athletes from Russia and Lithuania had failed tests and the name of Starykh, a former top junior performer who returned from four years in the wilderness to win the European sprint title last year, was strongly linked.

In a letter posted on the Russian Biathlon Union website the 26-year has now admitted to her involvement and has vowed to leave the national team for an "undetermined period" - despite protesting her innocence.

"I have received a notification [from the International Biathlon Union] in which it is stated that one of my tests gave a positive result," she admitted.

"This news was a major unexpected event for me and, believe me that I respectfully regret that this story is linked with my name.

"I do not have the right or the desire to let down the girls and the whole team."

The latest failed test is a blow for Russia ahead of the Games getting underway next week ©AFP/Getty Images



Starykh, who has asked for her 'B' sample to be assessed, will be replaced in the Olympic team by reserve athlete Galina Nechkasova.

In addition to being a further blemish for a country riddled with doping scandals in both summer and winter sports in recent months, the news is a particular blow because the Russian Biathlon Union is headed by billionaire Mikhail Prokhorov.

As well as vowing to resign if the team does not win at least two gold medals in Sochi, Prokhorov has spent millions re-structuring the programme following previous doping scandals in 2006 and 2009.

The other Russian athlete to have tested positive this time around is former world champion Ekaterina Iourieva who - although not selected for the Olympic team - now faces a lengthier ban as she has already been suspended for two years for using erythropoietin (EPO) in 2009.

The identity of the Lithuanian biathlete to have tested positive remains unknown but it is now thought that neither member of the Lithuanian Olympic squad - Tomas Kaukėnas or Diana Rasimovičiūtė - is implicated.