TOKYO -- The clock is ticking on the search for a missing Indonesian submarine as concerns grow over the air supply for the 53-member crew.
Indonesia's Navy chief commander Yudo Margono said in a news conference on Thursday that the oxygen on board the KRI Nanggala 402 is expected to last for 72 hours, which gives search and rescue teams until early Saturday to find and rescue the crew on board.
Contact was lost with the submarine while it was preparing for a torpedo-firing exercise in the early morning of Wednesday in waters north of Bali.
Indonesia's military spokesperson Achmad Riad had said in an earlier news conference on Thursday there are currently five ships and one helicopter conducting search missions near the spot where the submarine was last detected, and that a hydrographic survey ship was also on its way. Singapore and Malaysia have offered their assistance and are also sending vessels, the spokesperson said.
While some oil slicks were found yesterday and one of the search vessels reported detection of "underwater movement," Riad said the Nanggala had not been found yet. "The last position is estimated to be 23 miles north of Bali island," he said.
The last communication with Nanggala was at 4 a.m. on Wednesday. When the commander of the training task force tried to authorize the firing 25 minutes later, communication with the German-made submarine was lost. The submarine had been due to emerge from under water by 5:15 a.m.
Nanggala had been in service since 1981, but the navy chief commander said the vessel was "in good condition and ready to fight."
Indonesia's defence minister Prabowo Subianto, who also attended the news conference, said that while there are plans to modernise the country's fleets, "the existing fleets are being utilized optimally."
"I want to underline that submarine operations are the most complex, difficult and dangerous," Subianto said. "Many countries face [similar incidents], if I'm not mistaken [like] Russia. We pray that it can be found as soon as possible. There is still enough oxygen for a few days and we are optimistic to hope for the best."
Indonesia currently has a fleet of five submarines, and plans to operate at least eight by 2024 amid increasing challenges to its maritime claims -- most notably from China.
The Indonesian navy last year conducted a four-day exercise in the South China Sea, in a show of force against Chinese claims to the waters.
A portion of the exercise was conducted near Indonesia's Natuna Islands, where Chinese fishing vessels accompanied by Chinese-flagged government ships were repeatedly found. The borders of the exclusive economic zone around Natuna overlap with the "nine-dash line" map claimed by China.
In a letter to United Nations Secretary-General Antonio Guterres in May last year, Indonesia said it is "not bound" by the Chinese nine-dash-line claim, which "lacks international legal basis." The following month, Jakarta flatly rejected an offer to negotiate what Beijing called "overlapping claims."