Russian track rider Victoria Baranova failed a pre-Olympics dope test for testosterone and has been sent home by her national federation, the International Cycling Union (UCI) has confirmed.
"It is the result of a test carried out by the IOC before the Games. She has admitted to taking a banned substance and was sent home two or three days ago," UCI spokesman Enrico Carpani told Reuters.
Baranova was due to take part in the keirin at the Olympics.
"We have been working closely with the IOC and we are very happy with this collaboration, which strengthens our fight against doping," Carpani added.