All the survivors were found at sea some 72 hours after their boat had tipped over and were promptly evacuated to Batam, Riau Islands for further medical assistance, according to the Indonesian task force leading the drills.

“Three naval warships carried out search-and-rescue procedures at sea; we made use of various strategies and managed to evacuate all survivors to Batam,” the Navy First Fleet's Sea Combat Task Force commander Cdre. Krisno Utama told a press conference aboard the KRI Makassar warship on Monday.

Krisno said the fleet had managed to evacuate three fishermen and another man who was found further away floating on a piece of driftwood.

The SAR operation began when bridge officers aboard the KRI Bung Tomo-357 warship sighted a man overboard calling for help during a training regimen early on Sunday. The vessel deployed a rubber dinghy to rescue the man.

After the first survivor was retrieved, nearby vessel KRI Frans Keisepo-368 located another survivor floating 1.5 nautical miles away and set out to evacuate him.

At around 7:47 a.m. local time, Bung Tomo-357 sighted another two people in the water around the area where the first survivor was found. All were successfully evacuated.

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The four men were identified as Ikram, 35; Suryanto, 42; Hajra, 22; and Lasu Harjo, 29. They were all crew working aboard the fishing boat KM Rizky that had capsized.

The survivors were found in a weakened state but were nursed back to health before they disembarked in Batam to receive further treatment.

According to testimony from the survivors, they had set out to fish in open waters from Pangkal Balam, Bangka Belitung on July 28, before their boat suffered a leak and eventually sank. They had been in the water for roughly 72 hours before the naval vessels found and evacuated them.

The two warships and another that accompanied them were headed to Lingga regency in the Riau Islands to join the Super Garuda Shield exercises, the biggest two-week joint and combined-military drills to be co-hosted by the armed forces of Indonesia and the United States.

At least 4,000 US and Indonesian soldiers will be joined by forces from Australia, Singapore and Japan, with Canada, France, India, Malaysia, South Korea, Papua New Guinea, Timor Leste and the United Kingdom participating as observer nations.

The exercises will officially commence on Wednesday with an opening ceremony and last until Aug. 14.