Viacom said it sent a notice to YouTube on Friday morning, asking the popular video-sharing site to remove clips from Viacom-owned properties including MTV Networks and BET.

The media company controlled by Sumner Redstone said its pirated programs on YouTube has generated about 1.2 billion video streams, based on a study from an outside consultant.

A YouTube representative could not immediately be reached for comment.

"Filtering tools promised repeatedly by YouTube and Google have not been put in place, and they continue to host and stream vast amounts of unauthorized video," Viacom said in a statement.

The company is taking a hard stance against the Internet's most popular video service, which is renowned for its quirky, viewer-contributed video clips as much as for being a repository for unauthorized television shows.

"This is a negotiating tactic," UBS analyst Ben Schachter said. "We think a deal gets done ... The terms have major implications for the value of content online."

Viacom's move also runs counter to the strategies employed by other media companies, such as the Warner Music Group , Vivendi-owned (VIV.PA) Universal Music Group, and General Electric controlled NBC Universal, which have all landed deals with YouTube to test the service.

CBS Corp, which spun off from Viacom, also has a deal with YouTube.

In fact, CBS held a contest, in which YouTube users submitted videos they created. The winners will have their videos aired on CBS television. Hours after Viacom made its announcement, CBS said it would show the first winning video on Sunday.

Universal Music, most notably, threatened to sue YouTube last year, but reached a partnership with them. Its deal included taking a small stake in the company, according to several published reports.

Even as some media companies have decided to experiment with YouTube, other companies including News Corp., NBC and Viacom have held discussions to create its own online video business, sources have said.

Viacom last October had requested YouTube take down some of its video clips including those from hit shows from cable network Comedy Central, whose on-air talent joked about the site's popularity during the shows.

But thousands of clips remained on the service.

"YouTube and Google retain all of the revenue generated from this practice, without extending fair compensation to the people who have expended all of the effort and cost to create it," said Viacom.

Viacom added, "The recent addition of YouTube-served content to Google Video Search simply compounds this issue."

It was not immediately clear what percentage of YouTube's estimated 100 million views per day Viacom clips represents.

Google Chief Executive Eric Schmidt told analysts on Wednesday YouTube was in "various stages" of introducing technology, such a digital "fingerprinting" to identify copyrighted material.

"That is an area of big research in the computer science community and also a significant investment here at Google," Schmidt said after Google's quarterly results.