Greece's Supreme Court is due to rule whether to allow the extradition of a Russian cybercrime suspect to the United States to stand trial for allegedly laundering billions of dollars using the virtual currency bitcoin.

Alexander Vinnik appeared at the Athens court Wednesday amid an ongoing legal battle between the U.S. and Russia who are both seeking his extradition.

The 38-year-old former bitcoin platform operator denies any wrongdoing but is not contesting the Russian request on less serious charges.

He was arrested at a northern Greek holiday resort in July and a lower court has already approved his extradition to the U.S.

Greece's justice minister is likely to ultimately decide on whether Vinnik will be sent to Russia or the U.S.