A billion dollar infringement of copyright lawsuit disputing YouTube's ability to keep copyrighted material off its popular video-sharing internet site endangers how millions of internet surfers exchange information , YouTube owner Google Inc. said.

Google's attorneys made the claim in documents filed in U.S. District Court in Manhattan while the company responded to Viacom Inc.'s most recent lawsuit alleging that the World Wide Web has produced "an explosion of infringement of copyrights" by YouTube and others.

The back-and-forth between the companies has escalated since Viacom brought its lawsuit back in 2007, alleging it was due damages for the unauthorized showing of they're programming from MTV, Comedy Central and other networks.

In court documents presented to a judge late Friday, Google said YouTube "operates far beyond its legal responsibilities in helping content owners to protect their bodies of work."

Google has alleged that by attempting to make carriers and hosting providers responsible for online communications, Viacom "endangers the way millions of people lawfully exchange information, news, entertainment and political and artistic expression."

Google said YouTube was true to to the requirements of the 1998 Digital Millennium Copyright Act, saying the federal law was intended to protect companies like YouTube as long as they responded properly to content owners' claims of infringement.

On that account, Viacom says Google has set a dreadful example.

In a revised lawsuit filed last month, Viacom said YouTube consistently allows unauthorized copies of popular TV programming and films to be placed on they're internet site and viewed tens of thousands of times.

Viacom said it had discovered more than one hundred fifty thousand unauthorized clips of copyrighted TV programming - including "SpongeBob SquarePants," "South Park" and "MTV Unplugged" episodes and the documentary "An Inconvenient Truth" - that had been viewed "an astounding 1.5 billion times."

The company alleged its count of unauthorized clips comprises only a fraction of the content on YouTube that violates its copyrights.

It said Google and YouTube had done "little or nothing" to discontinue infringement.

"To the contrary, the availability on the YouTube site of a vast library of the copyrighted works of plaintiffs and others is the cornerstone of defendants' business plan," Viacom said.