Russian bobsledder Nadezhda Sergeeva has admitted an anti-doping violation and has been disqualified from the Winter Olympics.
As the International Olympic Committee (IOC) were meeting to discuss Russia's possible Olympic reinstatement, the Court of Arbitration said in a statement that Sergeeva had tested positive in an out-of-competition test for the banned heart condition product trimetazidine two days before her race.
Sergeeva finished 12th with Anastasia Kocherzhova in the women's bobsleigh competition in Pyeongchang on Wednesday.
"The athlete has admitted the anti-doping rule violation; she is disqualified from the womens bobsleigh event," it said.
"The results obtained by the team at the same event are disqualified with all resulting consequences; the athlete is excluded from Pyeongchang 2018; her accreditation shall be withdrawn.
"These proceedings shall continue before the CAS between the IBSF (International Bobsleigh and Skeleton Federation) and the athlete after the end of the Games; the IOC is no longer a party to this procedure.
"The athlete has accepted a provisional suspension beyond the period of the Games and reserved her 'rights to seek the elimination or reduction of the ineligibility period' following the conclusion of the Games." Russian bobsleigh official Sergei Zhurkin told reporters at the Olympic sliding centre: "At this moment she can't say where she made a mistake.
"In my opinion, maybe since the dose is very small that even means that she didn't drink the pill. As the doctors said, she could have got sprayed or smelled something or licked something. This is how minimal the dose is.
"Possibly she kept the pills that are allowed in the same container that was, somewhere, at some point, tainted.
"These are just my guesses. It's hard to say now. The doctors are investigating and probably all the medications that she had will be sent into the investigation as well as the container in which they were kept."
However, Stanislav Pozdnyakov, head of the Russian delegation in Pyeongchang, said the positive test was a result of negligence by Sergeeva, who had "let the team down".
Pozdnyakov said he had apologised to the IOC for the Russian's two doping violations but said they did not have a systematic character.