Defence Minister AK Antony on Wednesday condoled the death of naval personnel on the submarine that exploded and sank in the naval dockyard in Mumbai.
He briefed Prime Minister Manmohan Singh on the mishap before leaving for Mumbai where the incident took place.
"I have briefed the Prime Minister on the fire. I am just now going to Mumbai to see and get the details there," Antony told reporters outside Parliament House.
He said he was saddened at the tragedy of this magnitude which has happened in recent times.
"I also feel sad about those Navy personnel who lost their lives in the service of the country," he said without giving details
It is feared that 18 personnel on board have died.
Navy chief Admiral DK Joshi, who briefed Antony on the mishap, is already in Mumbai.
Navy sources, meanwhile, said here that the explosion took place in the forward section of the Kilo class INS Sindhurakshak submarine which houses torpedoes and missiles.
The Navy has ordered a board of inquiry to probe the explosion and subsequent fire on board the submarine.
Due to the explosion, the submarine has submerged at the dock with only a portion visible above the surface, a defence statement said.