Moscow, Nov 10 (UNI) A commission investigating the accident onboard the Russian nuclear submarine today said the probable cause was a malfunction in the vessel's fire safety system.
The tragedy occurred on Saturday, killing 20 people and injuring 22, when the Nerpa, Akula-class, nuclear-powered submarine was undergoing sea trials in the Sea of Japan.
At the time of the accident, 208 people, including 81 submariners, were onboard the vessel.
''The preliminary official conclusion is the unauthorised operation of the fire extinguishing system,'' Ksenia Gusentsova, spokesperson for the Chief Federal Inspector for the Primorye Territory, Russia's Far East, told RIA Novosti news agency.
A source in the investigating commission said, ''All the scheduled investigations will be completed within the next seven days.'' He said the chain of events would be reconstructed a day or two after the completion of the investigation, adding it had also been established that safety system of the submarine's nuclear reactor had been operating in automatic mode during the trials.
Earlier Capt 1st Rank Igor Dygalo, an aide to the Russian Navy Commander Vladimir Vysotsky, said the submarine's reactor had not been affected by the accident, which occurred in the nose of the vessel, and radiation levels were normal.
Meanwhile, Khabarovsk Governor Viktor Ishayev said the investigation revealed that the fire safety system had operated correctly and suggested that human error could have been a factor in the deaths.
''The ship has the latest fire extinguishing system, a computer-activated alarm,'' Mr Ishayev said.
''According to the investigation, there is no evidence that a person was involved in the system's operation,'' he added.
Investigators said the deaths were caused by suffocation after Freon gas was released following activation of the submarine's fire safety system.
He stressed that those working in the area that had donned breathing apparatus had survived, while those who failed to use safety equipment had all perished.
''You can't rule out that some of the civilians had not been issued with portable breathing apparatus or didn't know how to use them,'' Gennady Illarionov, a former naval submariner, said.
Tuesday has been declared a day of mourning in Primorye Territory (Russia's Far East), where the Russian Navy's Pacific Fleet is based.
UNI XC LPB GC2053