Authorities in the United States and Europe have announced the arrests of 179 suspects as part of a co-ordinated operation targeting individuals on the dark web.
Statements from Europol and the US Justice Department said that the international sting operation had also led to the seizure of more than $US6.5 million ($A9.1 million) in cash and virtual currencies, in addition to 500 kilograms of drugs such as fentanyl, heroin, cocaine and ecstasy.
Most of the arrests were made in the US - 121 - followed by 42 in Germany, eight in the Netherlands, four in Britain and three in Austria.
Several investigations are still ongoing.
The US Justice Department framed the operation known as DisrupTor as a major victory against the illicit drug market, which has increasingly moved online in recent years.
The dark web, also known as the darknet, is a part of the internet that isn't visible to search engines and can only be accessed through an anonymising browser called Tor.
It is often used for buying and selling drugs, pornography and other illicit goods.
"Operation DisrupTor is the United States government's largest operation to date targeting criminal activity on the Darknet, particularly opioid trafficking," the Justice Department said in a statement.
The operation involved at least 20 different US Attorneys' offices across the country and included an investigation that helped locate the person responsible for the killing of an elderly couple in the southern state of Georgia.
Australian Associated Press