NATO chief Jens Stoltenberg warned in an interview published Saturday that a Russian naval build-up threatens transport and communications links between alliance members.

"Russia has invested massively in its navy, especially submarines," Stoltenbergtold the Frankfurter Allgemeine Sonntagszeitung, adding that Moscow has deployed 13 additional submarines since 2014.

"Russia's submarine activity is now at its highest level since the Cold War," he said, adding that submarines were active in the Atlantic and Mediterranean and also "near our coastlines."

Stoltenberg: Russian naval buildup worrying

Stoltenberg suggested the submarine build-up threatened logistic and communications channels between North America and Europe.

"We are a transatlantic alliance, and we must therefore be in a position to transport troops and equipment over the Atlantic. For that we need secure and open seaways," he said.

In this strategic environment, NATO plans to establish a new Atlantic and logistics command. The location and structure of the commands is to be determined next year.

Decline in maritime capacity

The NATO chief also warned that since the end of the Cold War the alliance has lost some of its sea capability, especially in countering submarines.

On December 14, 25 member nations of the EU also inaugurated the PESCO pact - backed by NATO - to cooperate more closely on defence projects in the wake of Russia's annexation of Crimea in 2014.

A first batch of 17 projects includes a Belgian-led effort to develop submarine drones to tackle mines at sea.

Past efforts to integrate EU defence had been frustrated, first by French reluctance and later by British opposition to a "European Army."

Abstainers from PESCO are Denmark, Malta and Britain, which plans to leave the EU bloc in 2019.