“The submarine is now fully ready to carry out its tasks,” a senior executive at the Amur Shipyard, where the submarine was built, told RIA Novosti. “It will be handed over before the end of the year.”

When Russia makes the delivery, it will make India only the sixth operator of nuclear submarines in the world. Earlier this month, it launched the first of its own nuclear submarines.

The ten-year lease is worth $920 milion.

The Nerpa, an Akula II-class attack submarine, had originally been scheduled for delivery in 2008 but an accident earlier that year forced the Russian authorities to put it on hold.

Twenty people, mostly civilians, were killed when a fire-suppressant gas was released on the Nerpa during shakedown trials, in one of Russia’s worst naval accidents.