They will subsequently operate on their own under the supervision of Russian instructors.

On Nov 8, 2008, while the Nerpa was undergoing sea trials in the Sea of Japan, its on-board fire suppression system activated, releasing a deadly gas into the sleeping quarters. Three crewmembers and 17 shipyard workers were killed.

India reportedly paid $650 million for a 10-year lease of the 12,000-ton K-152 Nerpa, an Akula II class nuclear-powered attack submarine.

Akula II class vessels are considered the quietest and deadliest of all Russian nuclear-powered attack submarines.