Germany's federal Supreme Court said Internet service providers (ISP) could be made responsible for blocking websites offering illegal music downloads. However, the court says that ISPs should act only if copyright holders showed they had first made reasonable attempts to thwart such piracy by other means.

The federal Supreme Court dismissed two cases brought by music rights society GEMA against Deutsche Telekom and music companies Universal Music, Sony and Warner Music Group against Telefonica's O2 Deutschland.

It said the plaintiffs did not make enough effort to halt the copyright violations in the first place but it said Internet service providers could in principle be held responsible for blocking music illegally available on the Internet, even if the content remained available elsewhere.

GEMA, which acts to protect the rights of the owners of musical works, had demanded that Deutsche Telekom, Germany's largest telecoms company, block the website "3dl.am" because it offered access to copyright-protected music.

In a separate case, the music companies wanted O2 Deutschland to block access to "goldesel.to," part of the eDonkey network, a peer-to-peer file-sharing network for music.

"The Supreme Court has clearly stated that with regard to Internet service providers the reasonableness of a potential blocking has to be subject to strict scrutiny," Deutsche Telekom said in a statement.