The Pirate Bay is believed to be among those targeted Police have conducted a series of raids across Europe in one of its biggest crackdowns on file-sharing.
Police targeted 48 sites in countries including the Netherlands, Czech Republic and Hungary.
In Sweden, seven premises were raided including PRQ, which is believed to host Pirate Bay and whistle-blowing website WikiLeaks.
Co-ordinated by Belgian police, the operation was the culmination of a two-year investigation.
Off-network
Swedish prosecutors said the raids targeted a network called “The Scene” which offered downloads of films before they were available on DVD.
Umea University was among the premises targeted.
So far the raids have resulted in four arrests in Sweden and servers and computers have been seized from all seven Swedish premises, according to the Swedish police.
They said the raids had no links to WikiLeaks.
Belgian police are expected to make a statement later today.
Authorites across the globe have toughened their stances on illegal file-sharing in recent months, with governments including the UK, introducing tough new policies to deter individuals.
Mark Mulligan, an analyst with research firm Forrester, questioned the wisdom of both the raids and increased legislation.
“File-sharing operations are no longer centralised and any server is only ever going to be a cog in the wheel,” he said.
“This is just like customs seizing drugs – it doesn’t really affect the level of drug trafficking.”
“These things are necessary but the simple fact is that the judiciary and legislative bodies move much slower than technology. There are now dozens of different ways to share music off-network,” he added.
This article is from the BBC News website. © British Broadcasting Corporation, The BBC is not responsible for the content of external internet sites.