Indian Navy sailors work at the naval dockyard where a submarine caught fire and sank after an explosion on Wednesday in Mumbai.
Naval divers this morning found the bodies of three of 18 sailors who were inside the INS Sindhurakshak when a fire and multiple explosions sank the diesel-powered submarine.
The Navy has said finding any more survivors in the submarine is unlikely.
"The state of these two bodies and conditions within the submarine leads to firm conclusion that finding any surviving personnel within the submarine is unlikely," said a Navy statement.
"The damage and destruction within the submarine around the control room area indicates that the feasibility of locating bodies of personnel in the forward part of the submarine is also very remote as the explosion and very high temperatures, which melted steel within, would have incinerated the bodies too," the Navy said.
The Russian-built INS Sindhurakshak sank on Tuesday night following two big explosions in what was the biggest loss for the navy in four decades.
Divers entered the submarine on Wednesday evening, but their search for signs of survivors was near impossible. The dark, muddy water meant there is poor visibility, and because of the heat of the weapons that blew up, some hatches were melted shut.
But the Navy says it will continue its search.
"Eighteen brave sailors are feared to have lost their lives," Prime Minister Manmohan Singh said in his Independence Day speech on Thursday at the Red Fort in Delhi. "We pay homage to these brave hearts we have lost."
The navy says heavy duty pumps are being used to pump out water that flooded into the submarine after the explosions.
Because the submarine was docked, navy watchmen were on the submarine rather than the normal crew, Admiral DK Joshi, the navy chief, told reporters on Wednesday in Mumbai. At least some weaponry exploded in the near-simultaneous blasts, he added.
A video of the explosions filmed by bystanders showed an enormous ball of red and yellow fire rising hundreds of feet into the air.
Navy spokesman Narendra Vispute said the cause of the explosions was being investigated.
The 16-year-old submarine had been recently refitted in Russia at a cost of 80 million dollars and over a period of over two years. It returned to India in April, and had been certified for use by the Indian navy.