Since Alexander Vinnik’s arrest in a beachside village in northern Greece in late July, Moscow has also requested he be returned home.
Vinnik, who appealed Wednesday’s decision, is accused of running digital currency exchange BTC-e to facilitate crimes ranging from computer hacking to drug trafficking since 2011.
“We hope and expect a better outcome,” Alexandros Lykourezos, the lawyer leading Vinnik’s defence, told reporters.
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.