THESSALONIKI, Greece (AP) — Russian cybercrime suspect Alexander Vinnik, who is wanted in the United States in a $4 billion bitcoin fraud case, denied the charges against him Friday during an appearance in a Greek court to fight an extradition request.

Vinnik, 37, was arrested while on vacation in Greece on July25 and detained pending the extradition hearing following a request from U.S. Attorney's Office in the Northern District of California. According to U.S. authorities, he ran digital currency exchange BTC-e, and was allegedly involved in laundering money from criminal proceeds.

Complicating matters, Russia is also seeking his extradition on separate fraud charges. A panel of judges is expected to examine that request next week, which Vinnik's lawyer has said he will not challenge. In Greece, extradition disputes involving two or more countries are typically resolved by the justice minister.

Speaking during the hearing in the northern city of Thessaloniki, Vinnik told a panel of judges that he did not run the digital currency exchange, and said he had not transferred bitcoins. Asked by the judge why the system went down after his arrest, the suspect replied it could have been a coincidence and said he did not know who ran the exchange.

"How can one man have done all this alone?" he said, noting he was fighting the extradition request to the U.S. because he had "nothing to do" with the charges against him.

The prosecutor requested the American extradition request be accepted and said there were indications Vinnik was guilty.

The panel of judges said a decision would be made on Oct. 4.