By Karolos Grohmann

LAUSANNE, Switzerland (Reuters) – A decision by the Court of Arbitration for Sport (CAS) over Russia’s four-year ban for doping must come as soon as possible and leave no room for interpretation ahead of the Tokyo 2020 Games, the Olympic Committee said on Friday.

IOC Thomas Bach said the ruling should be watertight so as to leave no room for other legal challenges that would further delay decisions about how Russian will take part in the Tokyo 2020 Olympics.

“Unfortunately the speed of the procedure is not in our hands,” Bach told a news conference. “Of course we for a decision as soon as possible in to be able to make all the necessary arrangements.”

“What is as important for the IOC and the international federations is that we get a decision which does not leave room for any kind of interpretation. This must be a waterproof decision where everybody concerned knows what to do and what not to do.”

Russia, traditionally a powerhouse in many sports, has been embroiled in doping scandals since a 2015 World Anti-Doping Agency report found evidence of mass doping in Russian athletics.

On Thursday WADA formally asked CAS to on Russia’s four-year ban, after the agency last month handed down the punishment.

The move was expected after the Russian Anti-Doping Agency (RUSADA) sent a letter to WADA last month disputing the punishment, which bars Russia from competing in this year’s summer Olympics in Tokyo and the 2022 winter Games in Beijing.

Only Russian athletes who can prove they are competitors would be permitted to compete under the ban, and would have to do so as so-called ‘neutral’ athletes.

The IOC, however, is eager to avoid a of the run-up to the 2016 Rio de Janeiro Olympics where Russian athletes were filing appeals over bans days before they were due to compete.

A limited number of Russian athletes was permitted to compete at the 2016 Rio Games while Russia competed as a neutral team at the 2018 Pyeongchang Games.

“If there is room for interpretation then this interpretation will trigger the next CAS case and then I am not even speaking about potential appeal to other courts,” Bach said.

“Those would lead to real, confusion and potentially different interpretations by different federations.

“I hope that CAS manages this as soon as possible. The IOC make this interest very — to have this decision which leaves no room for interpretation.”

(Reporting by Karolos Grohmann; Editing by Ken Ferris)