Rescuers are continuing an urgent search for a missing Indonesian submarine that has less than a day's supply of oxygen left for its 53 crew.
The KRI Nanggala 402 disappeared on Wednesday after its last reported dive off the resort island of Bali, with concern mounting that the submarine may have sunk in waters too deep to reach or recover.
The Indonesian navy chief said the submarine was expected to run out of oxygen by roughly 03:00 local time on Saturday 24 April (20:00 BST Friday 23 April).
"We will maximise the effort today, until the time limit tomorrow (of) 3am," military spokesperson Major General Achmad Riad said.
The spokesperson refused to speculate on the submarine's fate, however there have been no signs of life.
A total of 24 ships and a patrol plane were mobilised for Friday's search, with the rescue party focusing on an area where an oil slick had been found.
An Australian warship, fitted with a sonar device and helicopter, is set to arrive to help the search, with a second Australian warship and Singaporean and Malaysian rescue ships also expected in the coming days.
Indonesia's President, Joko Widodo, asked all people to pray for the crew's safe return and has ordered all-out efforts to locate the submarine.
"Our main priority is the safety of 53 crew members," Mr Widodo said in a televised address on Thursday.
"To the family of the crew members, I can understand your feelings and we are doing our best to save all crew members on board."
The Indonesian navy has said it believes the submarine sank to a depth of 2,000-2,300 feet.
This is much deeper than its collapse depth – the depth at which water pressure would be greater than the hull could withstand.
Indonesian navy chief of staff Admiral Yudo Margono said an unidentified object with high magnetism was located at a depth of between 165 and 330ft, with officials hoping it was the submarine.
The cause of the disappearance is still uncertain, with the Indonesian navy stating an electrical failure could have meant the submarine was unable to execute emergency procedures to resurface.
Pentagon press secretary John Kirby said the US was sending airborne assets to assist in the search.
"We are deeply saddened by the news of Indonesia’s lost submarine, and our thoughts are with the Indonesian sailors and their families," Mr Kirby said.
The First Sea Lord of the Royal Navy, Admiral Tony Radakin, voiced his concern in a tweet.
He said: "I am deeply concerned by the reports of the missing submarine, KRI Nanggala.
"I wish every success to the Indonesian Navy in safely locating the boat and her crew, and to the Republic of Singapore Navy and Royal Australian Navy who are assisting."
Cover image: File photo of the missing Indonesian submarine (Picture: Stocktrek Images/Alamy Stock Photo).