The shadow of the Cold War has returned to the US coastline with the first detection in 15 years of Russian nuclear-powered submarines operating offshore.

With the irregular appearance of Bear strategic bombers in international airspace close to America and Britain, the emergence of two Akula Class submarines off the East Coast of the US — described by a Russian general as “a normal patrol” — has reawakened concerns about Moscow’s military aims.

The Royal Navy declined to say whether it had any evidence of Akula submarines returning to their Cold War haunts in the Iceland Gap, north of Scotland. “We don’t want to let them know that we know where they are operating,” a defence official said.

The Akula is capable of carrying torpedoes for attacking other submarines and surface vessels, as well as cruise missiles. It is also fitted with equipment to avoid detection. The American equivalent is the Los Angeles Class nuclear-powered submarine.

Commodore Stephen Saunders, a former submarine commander and editor of Jane’s Fighting Ships, said: “The arrival of Akula Class submarines off the US eastern seaboard is as much a political move by the Russian Navy as a military one, although these deployments would always have to be approved from high-up. It’s unquestionably the Russian Navy trying to raise its profile.”

He added: “The Russian Navy has been suffering from neglect for years, to such an extent that a Russian navy commander admitted in June that they might have to buy ships from abroad.”

One of the two submarines spotted off the US was an Akula II, a more recent version of the class that first came into service in the mid-1980s. Akula II class vessels are the quietest of Russian nuclear-powered attack submarines. Their construction began in 1991, but development work was suspended because of a lack of funding. The money was found in the 2007 budget and trials started last year.

Anatoli Nogovitsyn, Deputy Chief of Staff of the Russian Armed Forces, said that the submarine patrols had restarted in 2007 after the order had been issued by Vladimir Putin, then the Russian President, for strategic bomber patrols to be relaunched. RAF Typhoon and Tornado aircraft, part of quick-reaction alert units based in the UK, have had to scramble to chase away Bear bombers on a number of occasions since 2007 when they first started to approach British internationally recognised airspace.

US officials said that the two newly detected submarines had done nothing to provoke significant concern. One of the Akula submarines was in international waters about 200 miles off the US coast; the location of the other was not released.

However, a Pentagon official told The New York Times: “Any time the Russian Navy does something out of the ordinary, it is cause for worry.

“We’ve known where they were and we’re not concerned about our ability to track the subs, but we’re concerned just because they are there.”

Norman Polmar, an American naval historian and submarine warfare expert, told the newspaper: “I don’t think they have put two first-line nuclear subs off the US coast in about 15 years.”

Last year, in another sign of the Russian Navy trying to return to its old ways, the battle cruiser Peter the Great sailed to the Caribbean to participate in naval exercises with the Venezuelan Navy, along with the destroyer Admiral Chabanenko and other support ships. It was the first significant show of military force in the region since the end of the Cold War.

Commodore Saunders said that the Russians were trying to build a new generation of nuclear ballistic-missile submarines but that at present they had failed to develop a missile that worked. The Russians have carried out several aborted tests on a new Bulava submarine-launched strategic missile.

The most recent flight test, carried out on July 16, ended in the missile veering off course and blowing up mid-flight after being launched from a submarine in the White Sea. It was the sixth test of the Bulava missile to fail since 2005.

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