Norway said it has discovered 10 submarines of the Russian northern fleet heading toward the Atlantic Ocean in the biggest such operation since the Cold War.

The deployment began just before Russia's foreign minister and the commander of the northern fleet visited Norway to commemorate 75th anniversary of the Soviet liberation of Kirkenes from the Nazis.

Meanwhile, the recently floated Prince Vladimir submarine test-fired a Bulava ballistic missile from the White Sea near Arkhangelsk across 10 time zones to the Kamchatka peninsula across from Alaska on Wednesday.

Eight nuclear and two diesel submarines left bases near Murmansk early last week, and stayed submerged as they entered the Norwegian Sea, Norway's military intelligence agency told state broadcaster NRK.

That number would represent almost the entire underwater contingent of the northern fleet.

Some of the submarines are aiming to pass through the Greenland-Iceland-UK gap and enter the north Atlantic, according to Oslo.