The sailors aboard a missing Indonesian Navy submarine KRI Nanggala-402 have enough oxygen to last until Saturday, the Navy chief of staff Adm. Yudo Margono said on Thursday, while its Indonesian Military commander said the vessel was in good condition and battle-ready.
The defence officials were speaking at a news conference a day after the 44-year-old submarine went missing while conducting a torpedo drill north of the island of Bali. The chief of staff said weather conditions for the search and rescue efforts were calm.
"The submarine's oxygen reserve capacity in a blackout is 72 hours," Yudo told reporters.
"There's time until Saturday around 3:00 am. Let's hope we can find them before then."
However, defense analysts have warned that the vessel could have broken into pieces if it had sunk to depths believed to be as much as 700 metres (2,300 feet).
Australian Defense Minister Peter Dutton said initial reports raised the prospect of "a terrible tragedy".
The German-built submarine was scheduled to conduct live torpedo exercises when it asked for permission to dive. It lost contact shortly after.
Navy spokesman First Adm. Julius Widjojono said Thursday that search teams were focused on an area around the oil slick, but that the exact location of the vessel had yet to be pinpointed.
Six warships and a helicopter have been sent to look for the sub, the navy said.