Theories that the explosion of a faulty experimental torpedo caused the sinking of the Russian nuclear submarine Kursk reportedly were confirmed by acoustic spy tapes gathered by U.S. military intelligence, although U.S. officials deny the tapes' existence.

In Russia, Deputy Prime Minister Ilya Klebanov, chairman of the commission investigating the Aug. 12 disaster — when the submarine sank after shattering explosions — rejected reports that the Kursk was testing a new type of torpedo that some officers considered unstable. 

Russian officials maintain that the Kursk collided with a large object such as a foreign submarine or a World War II mine, but they have also raised the possibility that a torpedo inside the submarine misfired. 

"There were no new torpedoes on the submarine," Klebanov said after a commission meeting in St. Petersburg. He said the type of torpedoes aboard had been in service for 20 years, although he added they had been fitted with a new model of battery. 

U.S. Reports Claim Evidence Gathered By Spying Sub 

Tuesday's report, published in the New York Times, said that the USS Memphis, a U.S. Navy attack submarine monitoring the Kursk's naval exercises in the Barents Sea, had "sonar tapes and other recordings" that confirmed the predominant American theory. 

"According to the American theory," the Times wrote, "a rocket-propelled torpedo being loaded or launched as part of an exercise misfired, its engines or its fuel exploding." 

The article reported that the tapes are being examined at the National Maritime Intelligence Center in Suitland, Md., also the hometown of the National Security Agency ; although the Navy will not confirm the report. 

The Pentagon has been loath to comment on any of these reports as well. 

"I believe that's a city in Tennessee," a Pentagon official responded when asked about the Times article that said the USS Memphis was "one of two American submarines that were spying on the largest Russian naval exercise in years." 

The Pentagon routinely does not publicly discuss the operating locations or the missions of U.S. submarines. Nor do they publicly discuss what they know about the operating locations or missions of foreign submarine forces, as this could reveal the sources and methods used to gather that information. 

In fact, most nations are extremely secretive about information regarding their submarine forces. Some experts allege that this secrecy may have contributed to the failed efforts by Russia to respond effectively to the Kursk disaster, which could also lend support to the theory that the Russian Navy was experimenting with new weapons technology. 

Experimental Torpedo May Have Misfired 

While the Pentagon refuses to confirm any reports, the Times cited anonymous U.S. officials as theorizing that the Kursk was testing a revolutionary type of rocket-propelled torpedo which misfired, either its fuel or its engine exploding in or near the submarine. 

The Times article also quoted a Russian government investigator in Vladivostok as saying that the Kursk was testing an experimental weapons system. 

The U.S. and Russian sources cited by the Times did not elaborate further, but Internet reports during the crisis circulated rumors that the Russian submarine was test-firing a "supercavitation" torpedo. 

A recent article in the British journal New Scientist reported that the Russian navy was indeed working on such technology, which would involve launching a torpedo underwater from a catapult at speeds of at least 120 miles an hour. 

At such high speed, water would deflect from the torpedo's specialized blunt bow, creating a "supercavity", a large bubble of air that would enclose the torpedo as long as it maintained its speed. 

Once the supercavity formed, the torpedo's rocket engine would ignite and it would be capable of traveling at hundreds of miles per hour underwater. 

Projectiles traveling at such high speeds underwater could understandably revolutionize submarine warfare, and New Scientist also reported that American researchers had broken the underwater sound barrier using supercavitating bullets traveling at 3,000 miles per hour. 

While theories that the Russian Navy was experimenting with such supercavitation torpedoes in the Barents Sea are speculation, it is one of few hypotheses that account for the need to have a rocket-propulsion system attached to a torpedo.

Fox News' Dan Philbin at the Pentagon, the Associated Press and Reuters contributed to this report