The RIA Novosti news agency said the Defense Ministry brushed off inquiries about the report, which appeared on a U.S. Web site last week, and said questions should be submitted in writing.
The Kremlin's reaction came after U.S. officials denied outright the report that Akula-class sub sailed undetected around the Gulf in June and July. The report was posted by a conservative Web site, The Washington Free Beacon.
Military experts in Russia and Europe told the Moscow Times they doubted the sub could have spent so much time under the nose of the U.S. Navy because the Akula is not a particularly quiet piece of machinery. "They are unable to sit silently because their reactor cannot be turned off," said Christian Le Miere, a naval analyst at the International Institute for Strategic Studies. "A submarine of nearly 10,000 tons cannot easily enter coastal waters."
The Beacon stood by its report and dismissed contentions the story was designed to discredit President Obama's re-election campaign.
The report caught the attention of a U.S. senator, who called on the Navy to provide details of the supposed incursion and warned of what appeared to be a more aggressive military policy on the part of the Russians.
Sen. John Cornyn, R-Texas, a member of the Senate Armed Services Committee, on Sunday sent the letter to Chief of Naval Operations Adm. Jonathan Greenert requesting more information on the purported incident.
"This submarine activity reportedly occurred in June and July, simultaneously with incursions by Russian strategic bombers into restricted U.S. airspace," Cornyn wrote.
"The submarine patrol, taken together with the air incursions, seems to represent a more aggressive and destabilizing Russian military stance that could pose risks to our national security," Cornyn said.