MOSCOW (REUTERS) - Billionaire Oleg Tinkov, whose online bank is Russia's second biggest credit card issuer, pleaded guilty on Friday (Oct 1) to filing a false US tax return and agreed to pay US$507 million (S$688 million) in taxes, interest and penalties, the US Department of Justice said.

He had been accused of concealing US$1 billion in assets and income when renouncing his US citizenship in 2013.

Tinkov, whose businesses, including Tinkoff Bank, are held by his investment company TCS Group, was arrested in London in February 2020 in connection with the indictment, and released on bail as he was fighting acute leukaemia.

"Mr Tinkov is grateful for the opportunity to resolve this case in a humanitarian way and is hopeful that it will allow him to focus his energy on fighting his illness," his lawyers said in a statement.

His sentencing hearing is scheduled for Oct 29, which is expected to wrap up the case.

A spokesman for Tinkov said the businessman has enough funds to cover the fines without selling his assets, including shares in TCS.