The Indonesian Navy on Saturday confirmed that the submarine that went went missing with 53 crew members on board off the coast of Bali has sunk. The navy chief said fragments, including from inside the KRI Nanggala 402 vessel, had been recovered by a search party, adding that the submarine's oxygen reserves were believed to have run out

Authorities said the vessel had an oxygen supply of only three days after losing power, with that deadline expiring early on Saturday AFP reported.

Hundreds of military personnel, planes and warships, apart from rescue vessels from other countries, had been deployed to search for the missing German-built submarine. 

"We have raised the status from submiss to subsunk," Navy chief Yudo Margono told reporters, adding that the retreived items could not have come from any other vessel. 

"(The items) would not have come outside the submarine if there was no external pressure or without damage to its torpedo launcher," he added.

Navy officials diplayed a number of items recovered from the search missions, including grease used to lubricate the submarine's periscope, a piece of the torpedo as well as a prayer mat used by Muslims. 

One of only five in the country's fleet, the submarine disappeared during a live torpedo training exercise on Wednesday near the coast of Bali. 

An oil spill was spotted, hinting at where the sumbmarine would have sank as well as at possible fuel tank damage. There were concerns that the vessel could have sank because of water pressure, if it submerged below depths reaching 700 metres (2,300 feet), far below its limit. 

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The vessel was scheduled to conduct the training exercises when it asked for permission to dive. It lost contact shortly after.

Authorities have not offered possible explanations for the submarine's sudden disappearance or commented on questions about whether the decades-old vessel was overloaded.

The military has said the submarine, delivered to Indonesia in 1981, was seaworthy.