Crackdown on Darknet results in 17 arrests and closure of hundreds of sites selling illegal drugs and weapons

Police have closed hundreds of online "dark" markets selling illegal drugs, weapons and services, arresting 17 people in a massive international operation against the Tor network that allows users to be invisible online.

Investigators from the United States and 16 European countries, including France, Germany and Britain, on Thursday "undertook a joint action against dark markets running as hidden services on Tor network," the Europol police agency said.

Tor is an encryption service that masks a computer user's identifying IP address, allowing them to set up private web connections in what is known as the Darknet - a hidden network used for both licit and illicit ends.

"The action aimed to stop the sale, distribution and promotion of illegal and harmful items, including weapons and drugs, which were being sold on online 'dark' marketplaces," Europol said.

A total of 414 sites have been seized and closed down in the operation, codenamed "Onymous", but Europol declined to say how it had identified vendors and administrators on the supposedly anonymous Darknet.

The operation seized virtual Bitcoins, used to carry out transactions, worth US$1m, €180,000 (HK$1.7 million) in cash as well as unspecified drugs.