Organization pursues Internet service providers.

British music industry trade body the BPI has intensified its pursuit of illegal file-sharers by targeting Internet service providers for the first time.

The labels organization says it has written to two U.K. ISPs -- Tiscali and Cable & Wireless -- requesting that they suspend a combined total of 59 online accounts that are known to be making unauthorized downloads.

The BPI, which has so far focused on nabbing individual illegal file-sharers, said its dialog with the ISPs was essential in the battle against online piracy.

"We have said for months that it is unacceptable for ISPs to turn a blind eye to industrial-scale copyright infringement," said Peter Jamieson, BPI's chairman. "We are providing Tiscali and Cable & Wireless with unequivocal evidence of copyright infringement via their services. It is now up to them to put their house in order and pull the plug on these people."

The BPI searches for the unique IP addresses, on which email addresses are based, by scouring through peer-to-peer networks used by illegal downloaders. From the IP addresses, the BPI is able to pin down the ISP used and then asks the respective service provider to disclose the identity of illegal users.

It was at that point when the BPI approached Tiscali with 17 IP addresses and Cable & Wireless with 42 addresses.

The move comes after the BPI filed civil lawsuits against 139 illegal individual uploaders in four court cases; 111 of them have decided to settle out of court by paying up to £6,500 ($12,085) each.