NEW YORK -- U.S. prosecutors say two men have been charged with conspiring to commit money laundering by selling more than $1 million in Bitcoins to users of the black market website Silk Road, which lets users buy illegal drugs anonymously.

Authorities say Charlie Shrem was arrested Sunday at New York's Kennedy Airport while Robert Faiella was arrested Monday at his Florida home.

Prosecutors say in a news release that Faiella sold Bitcoins to users seeking to buy illegal drugs on the site.

They say Shrem bought drugs on Silk Road and helped Faiella exchange more than $1 million in cash for the tough-to-track digital currency Bitcoins so they could make illegal purchases.

Shrem's defence attorney did not immediately return a message seeking comment ahead of a court appearance scheduled for Monday. It wasn't immediately clear who would represent Faiella in court.

Authorities have said Silk Road's San Francisco operator generated more than $1 billion in illicit business from January 2011 through September on the website, which used Bitcoin before it was shut down.