Pyeongchang: The Russian curling medallist, who failed a preliminary drugs test on Sunday, has left the Winter Olympics. The news, which broke late on Sunday, has put his medal into jeopardy and raised growing questions about whether the International Olympic Committee was right to allow 168 Russians to compete under a neutral flag.

Alexander Krushelnitsky, who won a mixed curling bronze medal last week, is suspected of testing positive for meldonium, a banned substance that increases blood flow and improves exercise capacity — a result that will be confirmed when the results of his B-sample are known.

However on Monday morning his teammates on the Olympic Athletes of Russia team insisted he was innocent. “We were all shocked when we found out yesterday,” said Russian curler Viktoria Moiseeva. “Of course, we very much hope it was some kind of mistake. With us it’s not faster, higher, stronger; it’s about being more accurate. I can’t imagine what kind of drugs you could use in curling… so it’s very hard to believe.”

Russian curling federation president Dmitry Svishchev said Russian curlers had been tested on 22 January before flying out to South Korea and the tests were negative.

Krushelynytsky is awaiting the results of analysis of his B sample, which is expected later on Monday, before a violation can be confirmed.

Meldonium was banned in 2016 and led to Russian tennis player and former world No. 1 Maria Sharapova being barred from competition for 15 months.

The timing could not have been worst for Russia, who were hoping that their athletes would be able to march under their own flag at the closing ceremony next Sunday after the Russian Olympic Committee was banned from the Winter Olympics and ordered to pay $15m in costs in December after making what the IOC called an “unprecedented attack on the integrity of the Olympic Games and sport” following a massive state-sponsored doping programme that corrupted the Sochi Winter Olympics in 2014.