Russian Alexander Vinnik, who is accused of laundering billions using Bitcoin, outside a courthouse in Thessaloniki, Greece

A Greek court ruled on Wednesday that a Russian national accused of helping criminals launder billions of dollars using Bitcoin should be extradited to the United States.

Alexander Vinnik, who headed BTC-e, an exchange he operated for the cyber currency, was indicted by a US court in July on 21 charges ranging from identity theft and facilitating drug trafficking to money laundering.

"These accusations have nothing to do with me," Vinnik, 37, said after the ruling by a court in the northern city of Thessaloniki.

He said he would appeal.

"We have not yet seen the reasons for the judgement but the legal conditions for extradition have not been met," said Vinnik's lawyer Alexandros Lykourezos.

The Greek Supreme Court will name the date of the appeal proceedings within 20 days, according to a judicial source.

But the final decision on whether to extradite Vinnik will be made by the Greek justice minister.

Vinnik has been languishing in a Greek jail since his arrest on July 25 in the tourist resort of Halkidiki, near Thessaloniki.

According to US authorities, Vinnik "stole identities, facilitated drug trafficking, and helped to launder criminal proceeds from syndicates around the world".

BTC-e, founded in 2011, became one of the world's largest and most widely used digital currency exchanges, but according to the US indictment, it was "heavily reliant on criminals".

In addition, BTC-e "was noted for its role in numerous ransomware and other cyber-criminal activity," receiving more than $4 billion (3.4 billion euros) worth of Bitcoin over the course of its operation.

Vinnik was also charged with receiving funds from the infamous hack of Mt. Gox -- an earlier digital currency exchange that eventually failed, in part due to losses attributable to hacking.

The Treasury Department has fined BTC-e $110 million for "wilfully violating" US anti-money laundering laws, and Vinnik $12 million.

Treasury Secretary Steven Mnuchin hailed Vinnik's arrest, saying that cracking down on illegal uses of Bitcoin is a key goal of US regulators.

In August, Russia also requested the extradition of Vinnik, who is wanted there on separate fraud charges totalling 9,500 euros.

Vinnik rejected the accusations, but said in September he would accept extradition to his home country. The Greek judiciary will rule on Russia's request on October 11.