U.S. and European agencies shut down 410 hidden web domains, arrested 17 suspects and seized bitcoins worth about $1 million in a joint operation targeting the Tor network, which allows people to use the Internet anonymously.

The action, involving the Federal Bureau of Investigation, U.S. Homeland Security and Europol, closed down Silk Road 2.0, a so-called "dark market," according to a statement from Europol, an EU-wide law enforcement agency.

Criminals using the services "have considered themselves beyond reach," said Troels Oerting, head of Interpol's European Cybercrime Center. "We can now show that they are neither invisible nor untouchable."

Blake Benthall, an alleged operator of Silk Road 2.0, was arrested by U.S. prosecutors yesterday and charged with enabling users to buy and sell drugs and other illegal products.

Anonymous Silk Road customers used the bitcoin digital currency to buy heroin, LSD, fake passports and computer-hacking services, the U.S. said in charges against another alleged Silk Road operator Ross William Ulbricht. Tor, an acronym for The Onion Router, conceals users' Internet Protocol addresses by routing traffic through many servers.