A Russian nuclear-powered attack submarine armed with long-range cruise missiles operated undetected in the Gulf of Mexico for several weeks and its travel in strategic U.S. waters was only confirmed after it left the region, the Washington Free Beacon has learned.

It is only the second time since 2009 that a Russian attack submarine has patrolled so close to U.S. shores.

The stealth underwater incursion in the Gulf took place at the same time Russian strategic bombers made incursions into restricted U.S. airspace near Alaska and California in June and July, and highlights a growing military assertiveness by Moscow.

The submarine patrol also exposed what U.S. officials said were deficiencies in U.S. anti-submarine warfare capabilities—forces that are facing cuts under the Obama administration’s plan to reduce defense spending by $487 billion over the next 10 years.

The Navy is in charge of detecting submarines, especially those that sail near U.S. nuclear missile submarines, and uses undersea sensors and satellites to locate and track them.

The fact that the Akula was not detected in the Gulf is cause for concern, U.S. officials said.

The officials who are familiar with reports of the submarine patrol in the Gulf of Mexico said the vessel was a nuclear-powered Akula-class attack submarine, one of Russia’s quietest submarines.

A Navy spokeswoman declined to comment.

One official said the Akula operated without being detected for a month.

"The Akula was built for one reason and one reason only: To kill U.S. Navy ballistic missile submarines and their crews," said a second U.S. official.

"It’s a very stealthy boat so it can sneak around and avoid detection and hope to get past any protective screen a boomer might have in place," the official said, referring to the Navy nickname for strategic missile submarines.

The U.S. Navy operates a strategic nuclear submarine base at Kings Bay, Georgia. The base is homeport to eight missile-firing submarines, six of them equipped with nuclear-tipped missiles, and two armed with conventional warhead missiles.

"Sending a nuclear-propelled submarine into the Gulf of Mexico-Caribbean region is another manifestation of President Putin demonstrating that Russia is still a player on the world's political-military stage," said naval analyst and submarine warfare specialist Norman Polmar.

"Like the recent deployment of a task force led by a nuclear cruiser into the Caribbean, the Russian Navy provides him with a means of ‘showing the flag’ that is not possible with Russian air and ground forces," Polmar said in an email.

The last time an Akula submarine was known to be close to U.S. shores was 2009, when two Akulas were spotted patrolling off the east coast of the United States.

Those submarine patrols raised concerns at the time about a new Russian military assertiveness toward the United States, according to the New York Times, which first reported the 2009 Akula submarine activity.

The latest submarine incursion in the Gulf further highlights the failure of the Obama administration’s "reset" policy of conciliatory actions designed to develop closer ties with Moscow.

Instead of closer ties, Russia under President Vladimir Putin, an ex-KGB intelligence officer who has said he wants to restore elements of Russia’s Soviet communist past, has adopted growing hardline policies against the United States.

Of the submarine activity, Sen. John Cornyn (R., Texas), member of the Senate Armed Services Committee, said, "It's a confounding situation arising from a lack of leadership in our dealings with Moscow. While the president is touting our supposed ‘reset' in relations with Russia, Vladimir Putin is actively working against American interests, whether it's in Syria or here in our own backyard."

The Navy is facing sharp cuts in forces needed to detect and counter such submarine activity.

The Obama administration’s defense budget proposal in February cut $1.3 billion from Navy shipbuilding projects, which will result in scrapping plans to build 16 new warships through 2017.

The budget also called for cutting plans to buy 10 advanced P-8 anti-submarine warfare jets needed for submarine detection.

In June, Russian strategic nuclear bombers and support aircraft conducted a large-scale nuclear bomber exercise in the arctic. The exercise included simulated strikes on "enemy" strategic sites that defense officials say likely included notional attacks on U.S. missile defenses in Alaska.

Under the terms of the 2010 New START arms accord, such exercises require 14-day advanced notice of strategic bomber drills, and notification after the drills end. No such notification was given.

A second, alarming air incursion took place July 4 on the West Coast when a Bear H strategic bomber flew into U.S. airspace near California and was met by U.S. interceptor jets.

That incursion was said to have been a bomber incursion that has not been seen since before the Soviet Union collapsed in 1991.

It could not be learned whether the submarine in the Gulf of Mexico was an Akula 1 type submarine or a more advanced Akula 2.

It is also not known why the submarine conducted the operation. Theories among U.S. analysts include the notion that submarine incursion was designed to further signal Russian displeasure at U.S. and NATO plans to deploy missile defenses in Europe.

Russia’s chief of the general staff, Gen. Nikolai Makarov, said in May that Russian forces would consider preemptive attacks on U.S. and allied missile defenses in Europe, and claimed the defenses are destabilizing in a crisis.

Makarov met with Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, in July. Dempsey questioned him about the Russian strategic bomber flights near U.S. territory.

The voyage of the submarine also could be part of Russian efforts to export the Akula.

Russia delivered one of its Akula-2 submarines to India in 2009. The submarine is distinctive for its large tail fin.

Brazil’s O Estado de Sao Paoli reported Aug. 2 that Russia plans to sell Venezuela up to 11 new submarines, including one Akula.

Russian Foreign Minister Sergei Lavrov said Moscow’s military is working to set up naval replenishment facilities in Vietnam and Cuba, but denied there were plans to base naval forces in those states.

Asked if Russia planned a naval base in Cuba, Lavrov said July 28: "We are not speaking of any bases. The Russian navy ships serve exercise cruises and training in the same regions. To harbor, resupply, and enable the crew to rest are absolutely natural needs. We have spoken of such opportunities with our Cuban friends." The comment was posted in the Russian Foreign Ministry website.

Russian warships and support vessels were sent to Venezuela in 2008 to take part in naval exercises in a show of Russian support for the leftist regime of Hugo Chavez. The ships also stopped in Cuba.

Russian Deputy Premier Dmitri Rogozin announced in February that Russia was working on a plan to build 10 new attack submarines and 10 new missile submarines through 2030, along with new aircraft carriers.

Submarine warfare specialists say the Akula remains the core of the Russian attack submarine force.

The submarines can fire both cruise missiles and torpedoes, and are equipped with the SSN-21 and SSN-27 submarine-launched cruise missiles, as well as SSN-15 anti-submarine-warfare missiles. The submarines also can lay mines.

The SSN-21 has a range of up to 1,860 miles.