Updated

Russian bobsledder Nadezhda Sergeeva is the nation’s second athlete to fail a doping test at the Pyeongchang Winter Olympics – a day before the International Olympic Committee executive board will decide whether to reinstate Russia from its ban for widespread and systemic doping.

The Russian delegation at the Winter Olympics said Sergeeva, 30, tested positive for trimetazdine, a medication used for angina sufferers that is listed by the World Anti-Doping Agency as a banned substance affecting the metabolism. Sergeeva, who finished 12th in the two-woman bobsleigh, had given the drug-test sample on Sunday.

“She confirms she took no such medication and the team confirms she was not issued any medication,” said Russian Bobsled Federation president Alexander Zubkov, a former bobsledder who was stripped of two Olympic gold medals from the 2014 Sochi Games for the Russian doping scheme. “Federation representatives at the Olympics” are starting to prepare a defense, he said.

He added Sergeeva’s sample given five days earlier was negative.

"I can tell you that on the 13th it was clean, but on the 18th it gave a positive result for the heart medication,” Zubkov said.

The Guardian reported it is believed Sergeeva tested positive after ingesting the banned substance in a nose spray.

The disclosure of another positive doping test comes just 24 hours after Russian curler Alexander Krushelnitsky was stripped of an Olympic bronze medal for testing positive for the banned substance meldonium.

Alexander Krushelnitsky ap

Russian curler Alexander Krushelnitsky will give back his 2018 Olympic bronze medal after he failed a doping test last week. (AP)

Two other athletes – Slovenian hockey player Ziga Jeglic and Japanese speedskater Kei Saito – also left the games after testing positive.

The Russian team was barred from the Olympics in December for the large-scale doping operation at the Sochi Games, but the IOC invited 168 athletes from the country to compete independently under the Olympic flag.

Earlier this month, Sergeeva told the AP competitors from other countries had warmed to her after she passed IOC vetting for Pyeongchang, which included an examination of her drug-testing history.

"I don't know why, but they've started talking to us more than ever before. I feel it. Maybe it's a sign to them that we're clean," Sergeeva said. "There's a lot of people coming up and saying, 'We're happy you're here.'"

At the time, she was training in a T-shirt with the words "I Don't Do Doping."

Trimetazidine, the substance found in Sergeeva's sample, has been detected in previous doping cases. Chinese swimmer Sun Yang, an Olympic gold medalist, was banned for three months in 2014 by his country's sports authorities after testing positive for the substance.

Sun said he had been prescribed the drug for a medical condition and hadn't known it was banned. The perceived leniency of that three-month ban led to Sun receiving criticism from swimmers from other countries at the 2016 Olympics in Rio de Janeiro, where he won another gold medal.

Russia's bobsled program has been in the spotlight for drug use for several years.

Zubkov and four other bobsledders were disqualified from the 2014 Sochi Games for doping, though four other bobsledders have been reinstated. Another gold medalist, Dmitry Trunenkov, was banned last year for failing a doping test.

The Associated Press contributed to this report.