MOSCOW — Olympic discus silver medalist Darya Pishchalnikova has been given a 10-year doping ban after failing a drugs test for the second time, the Russian athletics federation (VFLA) said Tuesday. A sample taken from Pishchalnikova in May last year was re-tested and proved positive for the anabolic steroid oxandrolone, the VFLA said on its website (www.rusathletics.com). The VFLA annulled all of Pishchalnikova's results from May 20, 2012, meaning she is set to lose her London Olympic medal. The Russian served a doping ban of two years nine months from July 2008 to April 2011. The 27-year-old was among seven leading female Russian athletes found guilty of manipulating drug samples before the 2008 Beijing Olympics. She won silver at the 2007 world championships in Osaka, Japan, but was stripped of the medal after the International Association of Athletics Federations (IAAF) annulled all her results from May that year. In a separate case, European 800 meters champion Yelena Arzhakova was banned for two years, starting from Jan. 29, 2013, for showing an “abnormal haemoglobin profile in her biological passport,” the VFLA said. Arzhakova, 23, who finished sixth in the 800-mete Olympic final in London won by teammate Mariya Savinova, will have all her results from July 12, 2011 nullified, meaning she will be stripped of her European title. It was the latest in a series of doping offenses by leading Russian athletes. VFLA chief Valentin Balakhnichyov said his country, which will host the world athletics championships in Moscow in August, had been wrongly singled out for being too soft on drugs cheats. In an interview with Reuters last week, he sounded a warning to potential doping offenders, saying he expected more cases to be revealed in the future. “We do more drugs tests than any other country in the world. Some nations only do 500 tests a year. We did 3,500 tests last year alone and this year we plan to do over 4,000 tests in and out of competition, so don't be surprised if you hear about a few more suspensions coming our way,” he said. — Reuters