A number of Indian sailors are feared dead after an explosion and fire on board a submarine at a base in Mumbai.
Earlier the Navy said 18 crew members were trapped on the vessel, which is powered conventionally.
A team of divers was mobilised and 16 fire engines sent to the scene.
Later it was reported that bodies had been recovered.
“It’s a great loss to all of us, the greatest tragedy of recent times. I feel sad about that. I feel sad also, about those Navy personnel who lost their lives in the service of the country,” said India’s Defence Minister Arackaparambil Kurien Antony.
It is the Navy’s worst loss since the war with Pakistan in 1971.
The submarine had returned from an upgrade in Russia earlier this year. In 2010 there was another accident when a sailor was killed as it docked in port.
Just two days before this latest tragedy, the defence minister had been proudly unveiling a new aircraft carrier.
“It takes some of the sheen away because over the last few days there was a lot of satisfaction and pride in the country that though these were modest steps – launching an aircraft carrier is a big deal for a country that till 10 years ago was not even making a scooter, forget about a car,” said defence expert Uday Bhaskar.
With the launch of the Vikrant, India’s first home-built aircraft carrier, the country joined a select group of advanced nations.
It is a major boost to the development of India’s naval power at a time when its rival China is trying to extend its maritime dominance.