The FBI on Thursday said that it had concluded a two-year undercover operation targeting an online "carding" forum called Dark Market.

"Carding" forums trade stolen credit card information and other personal information; the term can also be used to refer to the process of verifying the validity of stolen credit card accounts by making discreet purchases.

Dark Market had over 2,500 registered members, according to the FBI, comprising a "virtual transnational criminal network. Over the past two years, the FBI has worked to infiltrate the network and identify its leading members. The agency said its operation resulted in 56 arrests around the world and saved some $70 million in potential losses.

"In today's world of rapidly expanding technology, where cybercrimes are perpetrated instantly from anywhere in the world, law enforcement needs to be flexible and creative in our efforts to target these criminals," FBI Cyber Division assistant director Shawn Henry said in a statement. "Leads in many of these investigations take us to the online world of Internet forums, where criminals go to engage in the business of selling and trading innocent person’s credit card numbers and other personal information. By joining forces with our international law enforcement counterparts, we have been, and will continue to be, successful in arresting those individuals and dismantling these forums."

Among the international law enforcement agencies assisting the FBI in its operation were the Computer Crime and Intellectual Property Section of the U.S. Department of Justice, the United Kingdom's Serious Organised Crime Agency, the Turkish National Police, and German federal and state police agencies.

Of the 206,884 complaints about Internet-related crimes received by the Internet Crime Complaint Center in 2007, more than 90,000, reflecting almost $240 million in reported losses, were referred to law enforcement agencies across the United States.