It was Australia’s worst maritime disaster: a US submarine torpedoed the ship unaware that it was packed with prisoners captured in Papua New Guinea.

The Montevideo Maru sank in July 1942. An estimated 979 Australians died, along with 33 Norwegian sailors and 20 Japanese guards and crew.

An Australian maritime archaeology group, Silentworld Foundation, organized the mission, helped by a Dutch deep-sea survey company called Fugro.

The wreck was located by an autonomous underwater vehicle (AUV) at a depth of more than 4,000m (13,123ft) - deeper than the Titanic wreck.

Capt. Roger Turner, a technical specialist in the search team, told the BBC that “it’s a war grave now, it’s a tomb that must be treated with appropriate respect”.

The closest the AUV got to the wreck was 45m, he said.

“It was a moment of emotion to see the images of the ship, the closed hatch covers where prisoners were kept on the voyage.”

The wreck will not be disturbed — human remains or artefacts will not be removed, Silentworld said.

Australian Prime Minister Anthony Albanese said that “at long last, the resting place of the lost souls of the Montevideo Maru has been found”.

“We hope today’s news brings a measure of comfort to loved ones who have kept a long vigil.”

The ship was sunk by torpedoes from the USS Sturgeon and went down rapidly.

Speaking by phone from the search vessel, Capt. Turner said that after being hit, the Montevideo Maru had assumed a steep angle within six minutes and disappeared below the waves in 11 minutes.

Just three lifeboats were launched and 102 Japanese crew and guards rowed to the Philippines.

Silentworld director John Mullen said families had “waited years for news of their missing loved ones”.

“Today, by finding the vessel, we hope to bring closure to the many families devastated by this terrible disaster.”

Silentworld said that in total the estimated 1,089 victims came from 14 nations and it has not been possible to trace all of their next of kin.

But it said descendants of the victims can register with the Australian Defense Force to get updates on the investigation and future commemorations.

The search began on April 6 in the South China Sea, 110km (68 miles) north-west of Luzon in the Philippines, and the wreck was located after 12 days.

It then took several days to verify the wreck using expert analysis from maritime archaeologists, conservators and other specialists, including ex-naval officers.

Scans of the wreck, including the hold, foremast and bow, matched features marked in drawings of the ship.

Capt. Turner told the BBC that the team were “euphoric”.

“Many years were invested in this, and more than that, the descendants of the victims number in the thousands.

“Two who were on board spent much of their lives researching the events, tracking down as many victims as they were able.”

Capt. Turner said residents of Rabaul in Papua New Guinea - a strategic hub captured by the Japanese in 1942 — still felt their connection to the Montevideo Maru disaster “very strongly today”.

“They conveyed how important this was to the descendants,” he said. The team’s elation at finally locating the ship was tempered by sadness at the scale of the disaster.

“We’re looking at the gravesite of over 1,000 people,” John Mullen told Australia’s ABC News.

“We lost nearly twice as many [Australians] as in the whole of the Vietnam War, so it’s extraordinarily significant for families and descendants,” he said.

“We had two people on board who had family members who were lost, so while on the one side there were cheers, on the other there were a few tears. It was very emotional.”