Russian hammer thrower Olga Kuzenkova, the 2004 Olympic champion, has been handed a two-year ban for doping, the country's athletics federation said on Tuesday.
The federation said that the samples which Kuzenkova gave for testing at the 2005 athletics world championships in Helsinki, Finland, contained banned drugs, without elaborating.
Kuzenkova's ban was backdated to March 27, 2013 and all of her results from August 12, 2005 until August 11, 2007 were cancelled.
The shot putter Svetlana Krivelyova, who won the bronze medal at 2004 Olympics, was also banned for two years from Tuesday as samples she had given in Athens also contained prohibited substances.
Again, the federation did not specify the drugs.
The anti-doping panel of the Russian athletics federation meanwhile said it had also banned 400m runner Yelena Churakova for two years from February 28, 2013.
Her samples taken in the training camp in Portugal in January contained testosterone and methandienone.
Russia has long been considered a black spot in world anti-doping, with a string of athletes found guilty of doping violations in recent years, but the International Olympic Committee (IOC) has said it is confident of a turnaround.
Moscow will host the World Athletics Championships this year while the Winter Olympics come to the Black Sea resort of Sochi next year, which the IOC hopes will prove a spur to more rigorous testing.