India on Wednesday inducted the Russian-origin nuclear-powered submarine 'Nerpa' into the Navy, joining the elite league of nations having such sophisticated warships.

Defence Minister A K Antony formally commissioned the Akula II class Nerpa, rechristened 'INS Chakra', into the Navy at the Ship Building Complex here.

"INS Chakra will ensure security and sovereignty of the country," Antony said after commissioning the vessel.

India has earlier leased and operated a Charlie Class Russian nuclear submarine from 1988 for training its personnel on such warships.

With the induction of INS Chakra, India has joined the elite group of nations with nuclear-power submarines after a gap of two decades.

With INS Chakra and the indigenous INS Arihant expected to start operational patrols soon, India will soon have two nuclear submarines guarding its vast maritime boundaries.

The Nerpa has been taken on lease from Russia for ten years and would provide the Navy the opportunity to train and operate such nuclear-powered vessels.

India had signed a deal with Russia in 2004 worth over USD 900 million for leasing the submarine.

It was expected to be inducted a couple of years earlier, but after an accident in 2008, in which scores of Russian sailors died during trials, the delivery schedule was changed.

Indian Navy crews have already been imparted training for operating the submarine in Russia. A crew of over 70 people, including around 30 officers, is required to operate INS Chakra.

The heart of the submarine is its nuclear reactor which has been made by Russia. Its displacement is around 8,140 tonnes.

With a maximum speed of 30 knots, the vessel can go to a depth of 600 metres and has an endurance of 100 days with a crew of 73.

The vessel is armed with four 533mm and four 650mm torpedo tubes.