Binary code in a woman's eye reflected from a computer screen in London. The United States on Tuesday unveiled what it said was the world's "largest" money laundering probe against the digital currency operator Liberty Reserve.

The United States on Tuesday unveiled what it said was the world's "largest" money laundering probe against the digital currency operator Liberty Reserve.

The Costa Rica-based entity, which operates a hugely popular online currency system outside of the control of national governments, is charged with running a "$6 billion money laundering scheme and operating an unlicensed money transmitting business," the US Attorney's office for New York said.

said Liberty Reserve processed at least 55 million illegal transactions for at least one million users "and facilitated global criminal conduct."

The probe involved in 17 countries "and is believed to be the largest money laundering in history," the prosecutor's office said.