Russia's team leader and driver Nadezhda Sergeeva takes a turn in the first women's unofficial bobsleigh training session during the Pyeongchang 2018 Winter Olympic Games. (Photo: Reuters)

Russian bobsledder Nadezhda Sergeyeva has tested positive for a banned substance at the 2018 Winter Olympics, Russia's bobsleigh federation said Friday.

"A doping test by the pilot of the Russian team Nadezhda Sergeyeva on 18 February gave a positive result for a heart medicine that is on the banned list," the federation said in a statement on its website, adding that a previous test on February 13 was negative.