PYEONGCHANG, South Korea -- A Slovenian hockey player has been expelled from the Olympic Games after allegedly testing positive for a banned substance, the international Court of Arbitration for Sport (CAS) said today.

Ziga Jeglic, who played on the Slovenian team that beat Team USA last week, was tested on match day, according to Team Slovenia press officer Brane Dmitrovic.

He was told to leave Pyeongchang, South Korea, today within 24 hours, the CAS said in a statement. Jeglic is the third athlete in the Winter Games who has been accused of doping.

CAS, the Switzerland-based body that reviews the evidence in such cases, said it has started an investigation.

Kei Saito, a Japanese short-track speed skater, was sent home after allegedly testing positive last week for acetazolamide, a diuretic and masking agent.

Russian Aleksandr Krushelnitckii, the bronze medalist in mixed pairs curling, allegedly had meldonium in his blood samples and has also left the games.

Meldonium appears to work by inhibiting the synthesis of a substance called carnitine, which the cells in the body need to burn fat to produce energy. The Russians argue that it wouldn’t help them.

Published studies say meldonium may be effective in treating heart ailments, strokes, diabetes and Alzheimer’s disease, as well as in improving people’s moods. But some experts said the evidence for such claims was scant and that it was not even clear whether the drug improves athletic performance.

Krushelnitsky, in a statement published on the Russian Curling Federation’s website, said he has never used any banned substances in his career.

"I can declare openly that never have I used banned substances or resorted to any other unsportsmanlike methods over the time I have been in sport," Krushelnitsky wrote.

The Russian National Committee is banned from the Pyeongchang games because of widespread, systematic doping during the Sochi 2014 Winter Olympics. Only athletes who were viewed to have not participated in any doping scheme were invited to attend these Olympics after careful vetting.

They participate under a neutral banner, the Olympic Athletes from Russia (OAR). If Krushnelnitckii is found to have purposefully taken the drug to enhance his performance, it could jeopardize Russia’s efforts to be reinstated into the Olympic family.

The Russian Olympic Committee (ROC) today said it will launch a comprehensive investigation into the incident to establish the details. “The concentration of meldonium found in the sample indicates that it was a single dose of the drug, which is not used for medical purposes, and it is absolutely meaningless from the point of view of achieving any therapeutic effect on the human body,” the ROC said in a statement.

Krushelnitckii, who trained in Japan before arriving in South Korea for the competition, has reportedly told officials that somebody must have laced his food or drink with the banned substance. Meldonium has been a banned substance for athletes in competitions since 2016.

The International Olympic Committee (IOC) has declined to comment on the ongoing investigation until it is complete, but said the new strict procedures will catch violators.

“It is always disappointing when these things happen, but it shows the systems are working here,” IOC spokesman Mark Adams said. The Russian Curling Federation is fully backing its curler’s claim of innocence and rallying to show support for the OAR curling squad.

"Today, practically all members of the Russian Curling Federation are flying to Pyeongchang to attend the CAS session,” Dmitry Svishchev, President of the Russia Curling Federation, told Russian news agency TASS. “We cannot leave these guys all alone in this situation." CAS has indicated it will release its ruling on Krushelnitckii by Thursday. The Olympic closing ceremonies will take place Sunday when the Russian athletes hope they will be allowed to march under the Russian flag.