ATHENS (Reuters) - A Greek court cleared the way on Wednesday for the extradition to the United States of a Russian, also wanted by Moscow, suspected of laundering billions of dollars in digital currency bitcoin.

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Alexander Vinnik, the alleged mastermind of a $4 billion bitcoin laundering ring, is one of seven Russians arrested or indicted worldwide this year on U.S. cybercrime charges.

Since his arrest in a beachside village in northern Greece in late July, Moscow has also requested he be returned home, as it has previously done with other nationals wanted by the U.S.

Vinnik, who appealed Wednesday’s decision, is accused of running BTC-e -- a digital currency exchange used to trade bitcoin -- to facilitate crimes ranging from computer hacking to drug trafficking since 2011.

U.S. authorities also linked him to the failure of Mt. Gox, a Japan-based bitcoin exchange that collapsed in 2014 after being hacked. They say Vinnik “obtained” funds from the hack of Mt. Gox and laundered them through BTC-e and Tradehill, another San Francisco-based exchange he owned.

Vinnik, who faces up to 55 years in prison if extradited to the United States, denies all charges against him, saying he was a technical consultant to BTC-e and not its operator.

A hearing date for the Russian extradition request on lesser fraud charges has not yet been set. While Vinnik denies those charges too, he consents to being returned to Russia.

Bitcoin was the first digital currency to successfully use cryptography to keep transactions secure and pseudonymous, making it difficult to subject them to conventional financial regulations.

Vinnik appealed to Greece’s Supreme Court, and his lawyers cited “insufficient indications, let alone evidence” against him presented in court.

“We hope and expect a better outcome,” Alexandros Lykourezos, the lawyer leading Vinnik’s defence, told reporters.

Should the Supreme Court uphold the decision to extradite him to the United States, the final decision is in the hands of Greece’s justice minister, who can approve extradition to one country and block the other in the event of competing requests.

“We have faith in the Greek justice system and a long road ahead of us,” said another of Vinnik’s lawyers, Xanthippi Moisidou.