Viacom demanded the removal Friday, after talks with YouTube and Google collapsed. "After months of ongoing discussions with YouTube and Google, it has become clear that YouTube is unwilling to come to a fair market agreement that would make Viacom content available to YouTube users," Viacom said in a statement.

The company added that Google's recent decision to add YouTube clips to the results returned on Google Video searches "compounds this issue." Viacom didn't elaborate on how the indexing of YouTube clips has affected the dispute, or on the sticking points of the negotiations.

So far, Viacom is the highest-profile U.S. company to demand a wholesale purge of its clips from YouTube, but Fox also recently subpoenaed the site to learn the identity of a user who posted clips of "The Simpsons" and "24." The "24" clips were posted on YouTube before the show aired on TV.

But two other large media companies, NBC and CBS, are working with YouTube to promote TV shows. In June, NBC arranged for its own channel on YouTube, which is being used to promote shows including "Saturday Night Live," "The Office," and "The Tonight Show with Jay Leno."

CBS last October placed more than 300 clips for shows including "Survivor," "CSI," and "Late Show with David Letterman," on YouTube--a move the TV network said boosted ratings.

Despite the tension between Viacom and YouTube, Viacom continues to work with YouTube parent Google to distribute clips from several MTV Networks shows, including "SpongeBob Squarepants" and "Laguna Beach."

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