The Russian navy says its submarines have increased their number of combat patrols to levels last seen during the Cold War.

Admiral Vladimir Korolyov, the commander in chief of the Russian navy, said their submarine crews spend more than 3,000 days on patrol last year.

He says they are now matching Soviet-era operational levels.

"It's an excellent level," said Korolyov in remarks carried by the state news agency.

After the 1991 Soviet collapse the Russian military was forced to scrap many relatively new ships and keep many more in harbour due to lack of funding.


But Russia has revived its military strength in recent years with a sweeping arms modernisation programme.

The increase in military capacity comes amid tensions with the West over Ukraine and ongoing operations in Syria.

Korolyov made the announcement after the launch of a new Yasen-class nuclear-powered attack submarine, called the Kazan.

He said the new ship was the most modern in the world saying its low noise level made it difficult to track.

"It represents the cutting edge of nuclear submarine design," Korolyov said in televised remarks.

The Russian navy is planning to commission seven Yasen-class submarines armed with torpedoes and long-range Kalibr cruise missiles.

The cruise missiles have been tested for the first time during the Russian campaign in Syria.