The Navy sources cited by the newspaper on Tuesday did not specify the components that needed the replacement but said they “were critical for the operations of the submarine.”

Neither Russian nor Indian defense ministries have officially commented on the report.

The Russian-built Akula II class nuclear attack submarine was inducted into the Indian Navy as INS Chakra in April.

The lease contract, worth over $900 million, was drawn up after an agreement between Moscow and New Delhi in January 2004, in which India agreed to fund part of the Nerpa's construction.

However, shortly after the start of sea trials in November 2008, an accident on board the submarine killed 20 sailors and technical due to a toxic gas leak when the automatic fire extinguishing system malfunctioned.

The Nerpa was finally handed over to India in January after prolonged and costly repairs.

The submarine has a maximum speed of 30 knots and a maximum operating depth of 600 m, while its endurance is 100 days with a crew of 73.

The vessel is armed with four 533-mm and four 650-mm torpedo tubes, although it cannot carry nuclear weapons under the lease provisions.

With the lease of the Nerpa, India became the sixth operator of nuclear submarines in the world, after the United States, Russia, France, Britain and China.

India’s domestically-designed INS Arihant nuclear submarine is expected to be ready for operational deployment in 2013 after final sea trials.