Russia says the main cause of the deadly fire on board a submersible which killed 14 crew on Monday was a fire in the battery compartment.
Defence Minister Sergei Shoigu also said the top-secret military craft was nuclear-powered but the reactor had been isolated from the fire.
Fourteen crew members died of smoke inhalation as a result of the fire on the submersible in the Barents Sea.
The craft is now at Severomorsk, the main base of Russia’s Northern Fleet.
“The main cause has been established – it was a fire in the battery compartment, and then it spread,” Mr Shoigu told President Vladimir Putin in a meeting on 4 July, according to the Kremlin website.
“The nuclear power unit on the vessel has been fully isolated and nobody is in that section. The crew took all the necessary measures to protect the unit, and it is in full working condition. This leads to us to hope that in quite a short time the vessel can be put back into service.”
Severomorsk was also home to the Russian Kursk nuclear submarine, which sank in 2000 killing 118 sailors.
The Kremlin had previously kept details about the vessel confidential, adding that it was in “the interests of the state and state security”.
The crew on board were involved in exploring the Arctic seabed, Russian government newspaper Rossiiskaya Gazeta reported.
In 2000, Mr Putin was heavily criticised for the way he handled the Kursk submarine disaster. Media reports at the time showed the president enjoying a holiday at a Black Sea villa as families of the victims demanded information about their relatives.
Accidents involving underwater vessels are rare. Here are some of the most serious:
- The Argentine navy’s ARA San Juan submarine with 44 crew disappeared during a routine patrol in the South Atlantic in 2017. The wreckage was found a year later
- All 70 crew aboard China’s Great Wall Ming-class submarine suffocated in 2003 when a diesel engine malfunctioned, consuming the vessel’s oxygen supply
- Russia’s Kursk submarine sank in the Barents Sea in 2000 after a torpedo exploded during an exercise, killing all 118 on board, including 23 who survived the blast but died due to a lack of oxygen
- The USS Scorpion sank in the Atlantic in 1968, possibly because a torpedo exploded, killing the 99 crew
- The USS Thresher sank during diving tests in 1963, killing all 129 on board – the biggest submarine death toll in history