Powered by a nuclear reactor, INS Arihant, literally meaning the destroyer of all enemies, can stay below the water for indefinite period.

Like all submarines, it is capable of firing missiles and torpedoes. It is fitted with latest weapons and sensors. The steel for the submarine was cut in 1998.

Hailing the achievement, Defence Minister A.K. Antony said the 'present situation in our neighbourhood' demanded greater acquisition of strategic assets.

Manmohan Singh and Antony did not take any country's name. But the biggest navy in Asia is China's. It is known to have 8-10 nuclear-powered submarines and 50-60 diesel-electric submarines.

The INS Arihant project was made successful by the close partnership of the Defence Research and Development Organisation (DRDO), the Department of Atomic Energy (DAE) and other public and private sector undertakings.

'Today is the first visible step towards realisation of creating the sea leg of our nuclear triad... It will provide us credible second strike capability,' said India's Navy chief, Admiral Sureesh Mehta.

The submarine will increase the reach and endurance of the Indian Navy, which seeks to become a true blue water navy and project its force beyond its borders.

The Russian help in the project was profusely appreciated by the prime minister.

Earlier, after the launch, Gursharan Kaur said: 'Mai pandubbi ke sabhi nausainkon ke ujjawal bhavishya ki kamna karti hun.' (I pray for the bright future of all the sailors onboard the submarine).