U.K. Internet users have been blocked from editing Wikipedia, and they're unable to access an article about an album by the German rock group, the Scorpions.

The U.K. regulatory agency, the Internet Watch Foundation (IWF), blacklisted the site Saturday, saying a user reported child sexual abuse and its hotline analysts determined that a picture of a nude girl on the album cover, included in the article, was a potentially illegal indecent image of a child under 18.

"The IWF does not issue takedown notices to ISPs or hosting companies outside the UK, but we did advise one of our partner Hotlines abroad and our law enforcement partner agency of our assessment," the group stated on its Web site. "The specific URL (individual webpage) was then added to the list provided to ISPs and other companies in the online sector to protect their customers from inadvertent exposure to a potentially illegal indecent image of a child."

The picture appeared on the Scorpions' album, Virgin Killer, which the band released 32 years ago.

U.K. users have reported performance problems with the entire Wikipedia site. The Wikimedia Foundation, which runs Wikipedia, said that 95% of U.K. Internet service providers use the IWF blacklist. Law enforcement, government agencies, and private groups also work with IWF to keep illegal content off the Web.

"We have no reason to believe the article, or the image contained in the article, has been held to be illegal in any jurisdiction anywhere in the world," Wikimedia Foundation's general counsel, Mike Godwin, said in a statement released Monday. "We believe it's worth noting that the image is currently visible on Amazon, where the album can be freely purchased by U.K. residents. It is available on thousands of websites that are accessible to the U.K. public."

The Wikimedia Foundation noted that external studies have ranked Wikipedia equal to, or better in quality, than conventional encyclopedias. The nonprofit group also said its editors monitor the site for fairness and independence.

The Wikimedia Foundation has urged the IWF to remove Wikipedia from its blacklist.

Wikipedia has been censored or restricted in other countries, including China. It also resisted a petition of more than 100,000 signatures requesting that it delete a picture of Muhammad.