Greece's Supreme Court on Wednesday ordered that a Russian accused of laundering $4 billion using bitcoin digital currency be extradited to the United States, a court source said.
Greece's justice minister will now have the final say on whether to extradite Alexander Vinnik, who headed BTC-e, an exchange for the cyber currency.
He was indicted by a US court in July on 21 charges ranging from identity theft and facilitating drug trafficking to money laundering.
Vinnik has been held in a Greek jail since his arrest on July 25 in the northern Greek tourist resort of Halkidiki. He denies the accusation.
Russia has also filed a demand to extradite Vinnik so he can stand trial on separate fraud charges.
Two Greek courts separately approved both extradition requests in October.
BTC-e, founded in 2011, became one of the world's largest and most widely used digital currency exchanges.
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".
It allegedly received 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 US Treasury Department has slapped BTC-e with a $110 million fine for "wilfully violating" US anti-money laundering laws. Vinnik himself has been ordered to pay $12 million.
In Russia, Vinnik is wanted on separate fraud charges totalling 9,500 euros.
He has said he would accept extradition to his home country.