Thousands of Web sites in Denmark and Europe have been hacked and defaced in apparent retaliation for the publication of cartoons satirizing the Prophet Mohammed.

According to Zone-H.org, an outfit that tracks server intrusions worldwide, more than 600 attacks against Web servers in Denmark have been recorded.

Servers in Israel and Europe have also been breached with pro-Islam messages denouncing the cartoons.

Internet security vendor F-Secure has published screenshots of the defacements, which carry a strong anti-Danish tone and support for the angry demonstrations that have erupted around the world.

One group calling itself the "Internet Islamic Brigade" posted an image of the London bombings on a popular Danish Web forum, threatening a similar attack "very soon."

Another site carried text that read, "don't ever talk about our prophet."

Most of the site defacements include images of Arabic lettering with English text and make direct mention of the publication of the cartoons by newspapers in Denmark.

Web site defacements have been used in online protests in the past and the latest activity is no surprise, said Zone-H tracker Roberto Preatoni.

"What came out from the survey is what [we] very much expected," he said, pointing out that the Internet has been used as an instrument to spread out cyber-protests related to what happens in the worldwide context.

Check out eWEEK.com's Security Center for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at eWEEK.com Security Center Editor Larry Seltzer's Weblog.

Copyright © 2006 Ziff Davis Media Inc. All Rights Reserved. Reproduction in whole or in part in any form or medium without express written permission of Ziff Davis Media Inc. is prohibited.