Details remain scant about Monday’s fire on the research submersible in the Barents Sea. Moscow has indicated the crew was studying the sea floor.
The Russian Defense Ministry said the sailors were killed by toxic fumes from the fire, and that others survived, although the military hasn’t said how many. Officials didn’t name the nuclear-powered vessel, but Russian media has reported it was Russia’s most secret submersible, the Losharik.
News about the accident wasn’t made public until Tuesday — a full day after it occurred. Russian President Vladimir Putin did not confirm until Thursday at the Kremlin that the vessel was nuclear powered.
Defense Minister Sergei Shoigu said the unit remains in working order after crew members took all measures to save it.
The submersible was able to return to port in the city of Severomorsk. Russian officials said the officers died of smoke inhalation.
The defense ministry says the fire broke out as the vessel was involved in data collecting in Russian waters.
Norwegian officials who track radiation in those waters say they have not detected any irregular radiation.