While no one has claimed credit for disabling the sites, Shumukh al-Islam, a primary site for al-Qaida messages and videos, has been dark since March 22, and four others are currently unavailable to access, The Washington Post reported Monday.
A minor Web site posted a message in an online forum claiming "the media arena is witnessing a vicious attack by the cross and its helpers on the jihadi media castles."
"It sure looks like a takedown," said former State Department counter-terrorism expert and current senior fellow at the Homeland Security Policy Institute at George Washington University, adding that, if a technical problem was being resolved by Web site administrators, "usually they will get on another site and say 'we've got technical problems.'"
The loss of information typically confuses and frustrates the readers of the Web sites.
"It leaves the rank-and-file to guess which messages and which messengers are genuine al-Qaida, and provides undercover operators with new opportunities to disrupt the movement," said A. Aaron Weisburd, senior fellow at the Homeland Security Policy Institute.
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