Greece's Supreme Court on Wednesday (15 November) postponed until December an extradition hearing for Russian cybercrime suspect Alexander Vinnik, wanted in the United States on charges of laundering billions of dollars' worth of bitcoin.

Vinnik is the subject of a judicial tug-of-war between the US and Russia, which is also seeking his extradition on lesser charges. The US is accusing Vinnik of laundering $4bn worth of bitcoin through BTC-e, one of the world's largest digital currency exchanges, which he allegedly operated.

Russia accuses him of a 667,000-ruble ($11,500) fraud. Greek courts have approved both extradition requests. The 37-year-old, who denies all charges, is appealing against the decision to extradite him to the US.

He is not contesting the Russian extradition request.

If Greece's Supreme Court upholds the lower court's order, a final decision will rest with Greece's justice minister. The Supreme Court set a new hearing date for 6 December.

"We asked the court to postpone the hearing today of the US request for the extradition of Vinnik, so that two essential witnesses can come who couldn't unfortunately come to Athens today," said Alexandros Lykourezos, one of Vinnik's lawyers.

"These witnesses will be able to testify and help the court understand the essential issues that arise from this case," he added.

The US Justice Department says Vinnik has been indicted by a grand jury in the Northern District of California on charges including money laundering, conspiracy to commit money laundering, and engaging in unlawful monetary transactions.

The charges carry maximum sentences of up to 20 years in prison.

Vinnik was arrested in July on a US request while he was on holiday with his family in the Halkidiki area of northern Greece, which is popular with Russian tourists.

In August, Don Fort, chief of criminal investigations at the US Internal Revenue Service (IRS) said: "Mr. Vinnik is alleged to have committed and facilitated a wide range of crimes that go far beyond the lack of regulation of the bitcoin exchange he operated.

"Through his actions, it is alleged that he stole identities, facilitated drug trafficking, and helped to launder criminal proceeds from syndicates around the world.

"Exchanges like this are not only illegal, but they are a breeding ground for stolen identity refund fraud schemes and other types of tax fraud.

"When there is no regulation and criminals are left unchecked, this scenario is all too common. The takedown of this large virtual currency exchange should send a strong message to cybercriminals and other unregulated exchanges across the globe."