As navy divers struggle to raise INS Sindhurakshak, a submarine that exploded on Wednesday, the 18 crewmen who were on board are yet to be "sighted or recovered". Prime Minister Manmohan Singh has expressed "deep regret" over the accident which the government has described as the "greatest tragedy in recent times."
The fully armed, diesel-powered world-class submarine went up in flames at the high-security naval dockyard in Mumbai shortly after midnight and later sank.
The submarine was fully loaded at the time of the incident; missiles and torpedoes stored in the forward section of the Sindhurakshak were detonated in the fire. Torpedoes are launched underwater to attack other submarines while missiles are used for long ranges above water.
A board of inquiry, which is due to report its findings within a month, is reportedly looking at whether the accident happened due to non-compliance of standard operating procedures or equipment failure. The possibility of sabotage, though, has almost been ruled out, according to the sources.
Meanwhile, divers have managed to open the main hatch and are flushing out water using heavy-duty pumps to raise the vessel which has also suffered extensive damage.
The INS Sindhurakshak had been returned by Russia less than a year ago after a major refit which cost India nearly Rs 480 crore.
The sinking of the submarine is a huge setback for the ambitious modernisation drive of the Indian Navy which has a total of 14 submarines of which only between seven and nine are operational at any point because of regular repair and refitting operations.