FIRE broke out on one of the Russian navy’s deep-sea research submersibles, and toxic fumes from the blaze killed 14 sailors aboard, Russia’s Defense Ministry said Tuesday, although it released few details about the disaster or the vessel involved.

The Defense Ministry did not say how many sailors were aboard the vessel during Monday’s fire, whether there were any survivors or if it was submerged at the time. But Russian media reported it was the country’s most secret submersible, a nuclear-powered vessel designed for sensitive missions at great depths.

President Vladimir Putin, who came under criticism for his handling of the Kursk nuclear submarine disaster in 2000 that killed 118 sailors, canceled a scheduled appearance and immediately summoned Defense Minister Sergei Shoigu for a briefing on the blaze, which was under investigation.

“Fourteen submariners have died of poisoning by fumes from the fire,” Shoigu told Putin during a televised meeting. “The fire was extinguished thanks to the crew’s resolute action.”

Putin ordered Shoigu to fly to the Arctic port of Severomorsk, the main base for Russia’s Northern Fleet where the vessel was brought, to oversee the investigation and report back to him personally.

“It’s a huge loss for the navy,” Putin said. “I offer my sincere condolences to the families of the victims.”

He added that the vessel had a special mission and an elite crew.

“It isn’t a regular vessel. It’s a research vessel with a highly professional crew,” Putin said, adding that seven of the dead had the rank of captain and two were awarded the nation’s highest medal, the Hero of Russia.

The fire occurred while the submersible was measuring sea depths in Russia’s territorial waters, the ministry said, adding that the vessel also is used for studying the seabed.

Russia’s RBC online news outlet and the Novaya Gazeta newspaper identified it as the nuclear-powered AS-12 Losharik.

The vessel is the most advanced Russian submersible, under a heavy veil of secrecy, and it is believed to have entered service in 2010. It is named after a Soviet-era animated cartoon horse that is made up of small spheres. (SD-Agencies)