Russia will lose the Olympic silver medal they won in the women's 4x400 metres relay at London 2012 after sprinter Antonina Krivoshapka retrospectively failed a drugs test.
The 29-year-old is the latest big name to be sanctioned following International Olympic Committee (IOC) re-testing of historic doping samples using the latest technology.
She is one of three to be disqualified from London 2012 today - alongside fellow Russian Vera Ganeeva, a discus thrower, and Turkish boxer Adem Kilicci.
Krivoshapka won silver in the British capital alongside Yulia Gushchina, Tatyana Firova and Natalya Antyukh but all four must hand back their medals.
Reanalysis of her samples led to a positive test for banned steroid dehydrochlormethyltestosterone, or turinabol.
She has also been disqualified from the women's individual 400m final, where she finished sixth.
In the relay, bronze medallists Jamaica should now be promoted to silver behind winners United States.
Ukraine's quartet are in line to move up from fourth to bronze.
The news is the latest doping scandal involving Russia, with the second part of the World Anti-Doping Agency's (WADA) McLaren Report alleging that the country had "corrupted" London 2012 on an "unprecedented scale".
Krivoshapka also won the 4x400m relay gold at the World Championships in Moscow in 2013, as well as the European title in Barcelona in 2010.
She won the individual 400m title at the European Indoor Championships in Torino in 2009.
Twenty-eight-year-old Ganeeva and 30-year-old Kilicci both also failed for turinabol.
Ganeeva made little impact at London 2012, finishing 23rd, while Kilicci reached the quarter-finals of the men's middleweight competition.
"The protection of clean athletes and the fight against doping are top priorities for the International Olympic Committee, as outlined in Olympic Agenda 2020, the IOC’s strategic roadmap for the future of the Olympic Movement," an IOC statement said.
"To provide a level playing field for all clean athletes at the Olympic Games Rio 2016, the IOC put special measures in place, including targeted pre-tests and the re-analysis of stored samples from the Olympic Games Beijing 2008 and London 2012, following an intelligence-gathering process that started in August 2015."
The most high profile athlete to fail a re-test is Jamaican sprinter Nesta Carter, whose disqualification from Beijing 2008 led to Usain Bolt losing a 4x100m Olympic gold medal.