Media in Indonesia reported that KRI Nanggala-402 became untraceable on April 22 during live torpedo training exercises off the Indonesian holiday island of Bali.
The 40-year-old submarine was found split into three pieces on the sea bed after five days of search efforts. All the vessel's 53 crew have been confirmed dead.
The same day, Prime Minister Pham Minh Chinh also cabled a message of condolences to President Joko Widodo over the tragedy.
