The major record labels have adopted a new tactic in their war against digital-music piracy in what some observers call a “declaration of war against the infrastructure of the Internet”.

Sony, Universal and RCA have filed suit in a New York court to get four ISPs (AT&T Broadband, Cable and Wireless, Sprint and Uunet Technologies) to block their users from viewing a Chinese-based music-sharing Web site,

It's the first time the music business has targeted ISPs – it has usually challenged music-sharing companies, such as Napster.

The legal challenge invokes a provision in the contentious US Digital Millennium Copyright Act. This gives US courts the power to force ISPs to take limited action to prevent users from accessing foreign sites that break US copyright laws.

The Digital Millennium Copyright Act is one of several moves that have been made to try to protect artists' copyright across borders. The World Intellectual Property Organization has also introduced the Copyright Treaty and Phonograms and Performances Treaty, with the aim of enforcing copyright and anti-piracy laws globally.

According to the New York Times, the ISPs haven't commented on the case but an insider told the paper that they were concerned by the ease with which Web sites could change their names. Such dodges would leave ISPs with the tricky task of tracking down the new URLs, should they have to take on the responsibility of blocking users from these sites.

The Electronic Frontier Foundation (EFF) said it opposed the lawsuit because it would establish a precedent for shutting down Web sites by alleging piracy. EFF Senior Intellectual Property Attorney Fred von Lohmann said: "The lawsuit shows that record labels have declared war on the infrastructure of the Internet in their campaign to stop the digital music revolution.”