July 2 (UPI) -- The Russian Defense Ministry said Tuesday more than a dozen sailors have died from smoke inhalation after their submersible vehicle caught fire.
Fourteen sailors died Monday after inhaling fumes on the vessel, which was designed to study the seafloor for the Russian Navy, officials said.
The ministry said the fire was extinguished "thanks to the self-sacrificing actions of the team," and the submersible is now at the Severomorsk naval base.
The cause of the fire is not yet known.
A submersible has limited power reserves and needs a mother ship to launch and recover. Monday's accident is the deadliest for any underwater Russian vehicle in the last decade.
A release of freon on a Russian submarine killed 20 people in 2008, including 14 civilians and six sailors.