A Russian news outlet, the RBC, cited an unnamed military source as saying the vessel was a nuclear-powered AS-12 submarine, but there was no official confirmation of that.
The incident took place on Monday in Russian territorial waters, and the fire has been extinguished. The vessel is now at the Russian Northern Fleet's base in Severomorsk on the Barents Sea, and an investigation has been launched to establish the cause, agencies Interfax, RIA, and TASS quoted the ministry as saying.
"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."
The statement, as cited by the agencies, did not identify the type or model of the underwater vessel.
In August 2000, the Russian nuclear-powered submarine Kursk sank to the floor of the Barents Sea after two explosions in its bow, killing all 118 crew aboard.