Officials in Russia are up in arms over a Greek court’s decision to allow the extradition of suspected money launderer Alexander Vinnik to the United States.

Vinnik was arrested in a beachside village in northern Greece last July on suspicions of laundering more than $4 billion through digital currency platform BTC-e. He was also suspected of facilitating hacking, fraud, identity theft, tax refund fraud, public corruption and drug trafficking activities during his time in the digital currency market, according to investigators.

Last week, a Greek court cleared the way for Vinnik to be sent to the United States, where he has been indicted on charges of operating unlicensed money service business, 17 counts of money laundering and related money crimes.

Russian ministry officials, however, called the Greek court’s decision a violation of the international law. The Russian Foreign Ministry has lodged its own extradition request for Vinnik, which it stated should be prioritized on grounds that Vinnik is a Russian citizen.