Indonesia has launched search efforts for a navy submarine that has gone missing, officials say.
It was taking part in a training exercise in waters north of the island of Bali but failed to relay results as expected.
The country's military chief told Reuters news agency that 53 people were on board the KRI Nanggala-402 vessel.
Officials have called on Australia and Singapore to help in the search, according to Reuters.
Defence officials from the two countries have not yet commented.
Local
media reports said the submarine was thought to have disappeared in
waters about 60 miles (96km) off the coast of Bali early on Wednesday
morning.
