"An explosion resulting in a major fire took place on board INS Sindhurakshak, a Kilo class submarine of the Indian Navy, shortly after midnight on 14 August 2013," said the Indian Navy in a statement.
"Fire tenders from the Naval Dockyard as well as the Mumbai Fire Brigade were immediately pressed into action.
"However, due to as yet unknown damage suffered as a result of the explosion, the submarine has submerged at her berth with only a portion visible above the surface."
The Indian Navy said: "About 18 persons were on board the submarine at the time of the accident and efforts are on to ascertain the safety of the personnel and salvage of the submarine."
"A Board of Inquiry is being instituted to investigate into the causes of the accident," it said.
In February 2010, a fire broke out aboard INS Sindhurakshak while she was in Visakhapatnam. One sailor was killed and two others injured.
Navy officials reported that the fire had been caused by an explosion in the submarine's battery compartment.
--IBNS (Posted on 14-08-2013)