PYEONGCHANG, Feb. 13 (Xinhua) -- Japanese short track speedskater Kei Saito has tested positive in the first doping case of the PyeongChang Winter Olympics Games and admitted that he will leave the Olympic Village.

The Court of Arbitration for Sport (CAS) announced on Tuesday that it has registered its first procedure on doping from the PyeongChang Games.

Saito has tested positive for acetazolamide, a diuretic, in an out-of-competition check, and "accepted on a voluntary basis to be provisionally suspended and to leave the Olympic Village," according to a CAS statement.

Japan's chef de mission Yasuo Saito said at a press conference that Saito had no idea where the substance was from and was surprised with the positive test.

"When it comes to prohibited substances or supplements, he is very aware of the substances and Saito had no idea why the samples tested positive and he could not understand where all that came from.

"Kei Saito could not understand how this came about, he could not think of any occasions or any possibilities that he may test positive for any of those substances."

The speedskater declined in a statement, which was read out at the press conference, that he had taken any banned substances.

"This is beyond my imagination this outcome. If something different was in my body it is totally out of my intention.

"I will fight in order to prove my cleanness. However if I seek to fight against this decision by CAS that consequently would lead to some annoyance to whole of our team. In that sense I will accept the decision and leave the Village by my own will."