Russian submarine fire: Fourteen sailors killed after huge blaze in deadliest naval incident since Kursk

Fourteen sailors have died after a huge fire on one of the Russian navy's submarines.

The Russian Defence Ministry said the blaze broke out on Monday while the vessel was performing tests in Russia's territorial waters.

It added that the fire was extinguished thanks to the crew's self-sacrifice.

The deep-sea submersible is now at the Arctic port of Severomorsk, the main base of Russia's Northern Fleet.

The ministry's statement said the submarine is intended for studying the seabed, but didn't give its name or type.

Authorities have not given a cause for the fire but said an official investigation had been launched.

The Russian navy uses Priz-class and Bester-class deep water vehicles, which have a hull built of titanium and are capable of operating at a depth of 1,000 meters (3,281 feet).

They are transported to the area of operation by a carrier vessel and can operate autonomously for up to 120 hours.

The blaze marks the deadliest Russian naval incident since 2008, when 20 died when a firefighting system was accidentally initiated while the Nerpa nuclear-powered submarine of Russia's Pacific Fleet was undergoing trials.

In the deadliest naval incident in post-Soviet Russia, the Kursk nuclear submarine exploded and sank on August 12, 2000 during naval manoeuvres in the Barents Sea, killing all 118 crew members.