The U.S. government on June 27 plans to auction almost 30,000 bitcoins, valued at $17.3 million, that were seized as part of the Federal Bureau of Investigation's crackdown last year on the Silk Road online marketplace for illicit drugs, the U.S. Marshals Service said Thursday.

In a statement, the Marshals Service confirmed it had taken custody of an additional 144,342 bitcoins that were seized as part of that operation. Those coins will also "be sold at some time in the future in a manner to be determined," according to James Margolin, spokesman for the U.S. Attorney's Office in Manhattan.

The Marshals Service said the first auction would take place over a 12-hour period on June 27 in nine blocks of 3,000 bitcoins and one of 2,657 coins. Interested buyers can place bids via a form at the U.S. Marshals website.

The winners will be notified on June 30.

The liquidation of such a large amount of bitcoins could depress the price of the digital currency.