(CNN) Dozens of Russian athletes have lost an eleventh-hour bid to join the Winter Olympics in Pyeongchang after the Court of Arbitration for Sport (CAS) rejected their appeal .

The appellants had asked CAS to overturn a decision by the International Olympic Committee (IOC) not to invite them over doping concerns, meaning they won't be joining the 150 competitors cleared to compete as "Olympic Athletes from Russia" (OAR).

It will be a crushing disappointment to the Russian appellants, some of whom traveled to South Korea in the hope they would be granted the right to compete.

One of the athletes' whose Olympic dream was ended Friday was Viktor Ahn, a highly decorated speed skater who was born in South Korea and competed for the country before becoming a naturalized Russian citizen.

Viktor Ahn of Russia competes during the men's 1500m preliminaries of the ISU World Cup short track speed skating event in Dresden, Germany, on February 6, 2015.

Russian official 'disappointed'

The head of Russia's bobsleigh federation, Sergey Parkhomenko, said the decision had a "political context" and the group would be taking legal action.

"We're disappointed with the CAS decision... we believed in better but received this instead. We will file lawsuits in other courts demanding compensation for material costs. We'll go to the federal Supreme Court of Switzerland," Parkhomenko said, according to Russian state news agency TASS.

Of the athletes and coaches whose appeals were thrown out Friday, 15 had previously had their lifetime bans for doping lifted by the Switzerland-based court.

The IOC refused to invite them to Pyeongchang however, saying it had lingering suspicions, so they went back to CAS to try and overrule the Olympic body.

In its decision Friday, the court upheld the IOC's right to exclude them, saying there was no evidence the IOC had "improperly exercised their discretion."

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The IOC welcomed the decision in a statement, saying it "supports the fight against doping and brings clarity for all athletes."

Craig Reedie, President of the World Anti-Doping Agency (WADA), said the "timing of these decisions just before the opening ceremony in Pyeongchang is good as it will reassure athletes and others that only Russian athletes (who) have met strict anti-doping guidelines will be participating in the Games."

Some of those athletes have already been in action. Though the Games don't officially kick off until Friday night local time, preliminary matches began in several sports earlier this week.

In events Thursday and Friday, Russian curlers, ice skaters, ski jumpers and downhill skiers all took part in qualifying rounds, while many more athletes have been training on the Pyeongchang slopes and arenas.

Marika Pertakhiya, an Olympic Athlete from Russia, jumps during the women's moguls qualifying at the 2018 Winter Olympics in Pyeongchang, South Korea on February 9, 2018.

Widespread ban

Russia was banned from taking part in the Games in December after the IOC found the country had engaged in "systemic manipulation" of anti-doping rules, though Russian athletes who could prove they were clean were "invited" to compete as OARs.

They will wear a uniform with that name on it, and the Olympic anthem will be played at any medal ceremonies for Russian athletes.

But dozens of Russian athletes who had hoped to compete under the neutral flag were deemed ineligible by the world Olympic body.

"The list on which the Invitation Review Panel (IRP) based its considerations (on) covers a wide range of information," said Valérie Fourneyron, the Chair of the International Testing Agency (ITA).

"It includes, for example, evidence of suspicious Steroid Profile values, DNA inconsistencies and irregularities of the Athlete Biological Passport, as well as evidence provided necessarily need to be transmitted to the athletes."

The IOC confirmed that only athletes who have "fulfilled the pre-games testing requirements," including the IRP's criteria, "as well as the required reanalysis from stored samples," would be allowed to compete at the Games.

More than 150 Olympic Athletes from Russia are currently listed on the official Pyeongchang Games website.

Last month Russian President Vladimir Putin admitted there had been " instances of doping use in Russia ," but said the issue was a global problem.

Addressing supporters in Moscow, Putin said "there were instances of doping use, true -- I want the audience to know this and the whole country to know this."

But he added "there are many such examples around the world, but no one is making a big show of it."