Fourteen Russian sailors on board a submersible military vessel were killed after a fire broke out and they suffocated on the fumes.
The deep-sea research vessel was carrying out a survey in Russia's territorial waters when the blaze erupted on Monday, the defence ministry was quoted as saying by Russian news agencies.
The fire was later extinguished and the submersible subsequently docked at the Northern Fleet's base in northwestern Severomorsk on the Barents Sea. An investigation was launched to establish the cause of the fire.
"Fire broke out on board a deep-water scientific research vessel that was studying the marine environment of the world ocean on behalf of the Russian navy," Interfax cited a ministry statement as saying. "Fourteen submariners died as the result of smoke inhalation."
Russian President Vladimir Putin will meet Defence Minister Sergei Shoigu soon, state-run RIA Novosti news agency quoted the Kremlin as saying later on Tuesday. The Kremlin gave no reason for the planned meeting.
The report came after Russian news outlet RBC cited an unnamed military source as saying the vessel was a nuclear-powered AS-12 submarine, but there was no official confirmation.
The statement did not identify the type or model of the vessel.
Al Jazeera's Step Vaessen, reporting from the Russian capital Moscow, said the AS-12 was known in the West as a "spy submarine".
"It is not exactly clear what exactly this vessel can do, but there has been a lot of concern, especially in the United States, that in the case of a global conflict this submarine could cut off all the major internet data and other important data that are used by governments and other important institutions," she said.
The deadly incident echoes one in August 2000 when a Russian nuclear-powered submarine Kursk sank to the floor of Barents Sea after two explosions in its bow, killing all 118 sailors on board.-Al Jazeera