Authorities now expect to carry out an evacuation process to recover the KRI Nanggala-402 submarine and its crew when they pinpoint its exact location, Indonesian Navy Chief of Staff Yudo Margono said.
The latest update came as hopes faded for the 53 crew members, who were expected to have run out of oxygen early on Saturday. So far, no sign of them has been found, Yudo said.
Some warships deployed to the Bali Sea, where the submarine was last contacted Wednesday, will be used to help find the vessel by detecting metal or magnetic objects in the sea.
Six pieces of debris believed to be from the submarine were presented to journalists at the news conference. The items were found about two miles from the spot where the submarine started to dive before it went missing, Yudo said, and included a bottle of grease, part of a torpedo launcher, part of a metal tube, prayer mats and fuel.
The debris was found floating at a location where the sea is 850 meters (930 yards) deep, he said, which would make a possible evacuation very "difficult."
It is believed that explosion have not occurred on the submarine but that heavy pressure on the vessel likely created a crack through which some items escaped.
On Friday Indonesian search teams said they had identified an area where the submarine could be located.
The area of interest is about 40 kilometers north of Bali, where oil had been spotted on the surface of the water near the dive point, and where an object likely to have come from the submarine was detected, according to military sources.
More ships with high-tech capabilities also joined the search efforts Friday, creating a search team consisting of 21 Indonesian warships, a submarine and additional vessels from Indonesia's police and rescue department.
Two Australian warships have also joined the search efforts.
The United States is also sending aircraft to assist in the search for the missing submarine.