VLADIVOSTOK, November 15 (RIA Novosti) - Final trials of Russia's Nerpa nuclear attack submarine, damaged in a fatal accident during tests in November last year, will begin late next week, the submarine's producer said on Sunday.

On November 8, 2008, while the Nerpa was undergoing sea trials, its onboard fire suppression system activated, releasing a deadly gas into the sleeping quarters. Three crewmembers and 17 shipyard workers were killed. There were 208 people, 81 of them submariners, onboard the vessel at the time.

"Initially, the submarine's state trials were scheduled to start on November 15. But later a decision was made to postpone them for a week. In about 5-6 days the submarine will leave the dock for state trials, which will last about two weeks," a spokesman for the Amur shipyard said.

Following the repairs, which cost an estimated 1.9 billion rubles ($65 million), the submarine was cleared for final sea trials before being commissioned with the Russian Navy in December 2009 and will be subsequently leased to the Indian Navy under the name INS Chakra.

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.