Rescue teams, with support from the U.S. and other countries, desperately were trying to locate a missing Indonesian Navy submarine on Friday.
It is somewhere in the Bali Sea with 53 crew on board, whose air could run out as early as Saturday morning.
There are fears the vessel already could have been crushed by water pressure.
The 44-year-old KRI Nanggala-402 disappeared Wednesday during preparations for a torpedo drill.
The commander of the Indonesian submarine fleet, Harry Setiawan, is aboard.
“So far we haven’t found it… but with the equipment available we should be able to find the location,” Achmad Riad, a spokesman for the Indonesian military, told a news conference.
Something with “high magnetic force” was reported “floating” at a depth of 50-100 meters, Indonesian Navy Chief of Staff Yudo Margono said, and an aerial search had earlier spotted an oil spill near the submarine’s last location.
An Indonesian defense expert said the crew could still be found alive.
“But if the submarine is in a 700-meter sea trough, it will be difficult for them to survive because underwater pressure will cause cracks and ruptures of the steel hull,” Connie Rahakundini Bakrie said.
Australia, India, Malaysia, Singapore and the United States have sent specialized ships or aircraft in response to Indonesian requests for assistance.
The U.S. Defense Department is sending “airborne assets” to help, according to a Pentagon spokesman.
White House national security adviser Jake Sullivan told Indonesian Foreign Minister Retno Marsudi on Thursday the “United States would do everything possible to support Indonesia’s search and rescue effort,” a spokeswoman said.
The diesel-electric powered submarine could withstand a depth of up to 500 meters (1,640 ft) but anything more could be fatal, Navy spokesman Julius Widjojono said.