In a statement released on Wednesday evening, the Indonesian Ministry of Defense said that the KRI Nanggala-402, a German submarine, had lost contact during an exercise in the Bali Strait – a stretch of water between the islands of Java and Bali connected to the Indian Ocean and the Balisee.
The submarine requested permission to dive or go under at 03:00 local time (15:00 ET) before losing contact. The statement added that an oil spill was seen in the air force near the dive site, around 7am local time.
Earlier on Wednesday, military chief Hadi Tjahjanto told Reuters that they were “looking for 53 people in the waters of Bali, 96 km from Bali”.
Singapore and Australia offered to provide assistance.
The 1 395 ton KRI Nanggala-402 was built in 1977 by the German shipbuilding company Howaldtswerke-Deutsche Werft (HDW) and joined the ranks of the Indonesian navy in 1981, according to the Ministry of Defense.
According to the Indonesian Cabinet website, the submarine underwent a two-year repair in South Korea that was completed in 2012.
In the past, Indonesia has managed a fleet of 12 submarines purchased from the Soviet Union to patrol the waters of its vast archipelago.
But now it has a fleet of only five, including two German-built Type 209 submarines and three newer South Korean ships.
Indonesia has tried to upgrade its defense capability, but some of its equipment that is still in service is old and there have been fatal accidents with especially obsolete military transport aircraft in recent years.