WELLINGTON, New Zealand (AP) — A fuel spill is “highly probable” after a New Zealand navy ship grounded, caught fire and sank off the coast of Samoa, the Pacific island nation's acting prime minister said late Sunday.

All 75 people on board the HMNZS Manawanui were taken to safety on life boats. The ship, one of only nine in New Zealand's navy, was the first the country has lost at sea since World War II.

Officials in Samoa are assessing the environmental impact in the area where the ship sank on Sunday morning, acting Prime Minister Tuala Tevaga Iosefo Ponifasio said in a statement.

The vessel's passengers — including civilian scientists and foreign military personnel — evacuated in “challenging conditions” and darkness, New Zealand’s Chief of Navy Rear Admiral Garin Golding told reporters. The vessel was about a mile from shore when it grounded on a reef and began taking on water, and it took five hours for the first survivors to reach land, he said.

One person was treated in hospital for minor injuries and has been discharged, the military said. Up to 17 others sustained lacerations, contusions, or suspected concussions. An Air Force plane carrying 72 of those on board the ship touched down at an air base in Auckland on Monday night.

New Zealand will hold a court of inquiry into the loss of the ship. The cause of the accident is not known, but Defence Minister Judith Collins told 1News on Monday that she had been told a loss of power to the vessel had led to its grounding.

The specialist dive and hydrographic vessel had been in service for New Zealand since 2019, but was 20 years old and had previously belonged to Norway, Collins said. It was surveying a reef off the coast of Upolu, Samoa’s most populous island, when it ran aground on the reef.

Photos and videos taken from the shore appeared to show the ship listing before disappearing completely below the waves, with a large plume of smoke rising where it sank. Collins said Sunday that she did not expect the vessel could be salvaged.

“This is a ship that unfortunately is pretty much gone,” she told reporters.

There was “a lot of fuel” on the ship and efforts had turned to assessing the potential environmental impact, Collins told Radio New Zealand Monday. New Zealand “would obviously have to front up” if there was a spill, she added.

The military said the ship, purchased for $100 million NZ dollars ($61 million) in 2018, was not covered by insurance.

The state of New Zealand’s aging military hardware has prompted warnings from the defense agency, which in a March report described the navy as “extremely fragile,” with ships idle due to problems retaining the staff needed to service and maintain them. Of the navy’s eight remaining ships, five are currently operational.

Golding said the HMNZS Manawanui underwent its usual maintenance before the deployment. The ship’s captain was an experienced commander who had worked on the vessel for two years, he said.