Moscow, July 10 (RIA Novosti) A Russian nuclear submarine that is to be leased to India and which was damaged in an accident that killed 20 people resumed sea trials Friday after extensive repairs, a defence official said.

'The sea trials of the Nerpa nuclear submarine will continue for two weeks. All the damage on the vessel has been repaired,' the official told RIA Novosti.

Following the repairs, which cost an estimated $60 million, the submarine was cleared for final trials before being commissioned with the Russian Navy and leased to the Indian Navy by the end of 2009.

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

On Nov 8, 2008, while undergoing trials in the Sea of Japan, an on-board fire suppression system went off, releasing deadly gas into the sleeping quarters. About 20 people - three crew members and 17 shipyard workers - were killed. There were 208 people on board the vessel at the time of accident.

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