WHAKATANE, New Zealand — A second land search of New Zealand's volcanic White Island on Sunday failed to locate the bodies of the last two victims of an eruption that claimed the lives of at least 15 people, most of them tourists.

Two four-person teams landed on the island by helicopter early Sunday and searched a location thought to be the most likely place where one of the bodies might be. The teams, wearing heavy protective clothing, were using breathing gear that allowed them to search for only 75 minutes.

They were unable to locate either body and returned to the New Zealand mainland, where they underwent decontamination after being exposed to toxic ash and gases.

“We have always anticipated recovering all bodies from the island and we remain deeply committed to that goal to allow families some closure,” Police Deputy Commissioner John Tims said.

Later Sunday, divers were due to resume their search of waters around the island despite near-zero visibility that hampered their efforts Saturday. Rescue teams had reported seeing a body in the sea a day after Monday’s eruption.

While scientists said the possibility of a second eruption appeared to have receded, they said White Island remains “highly volatile.”

Police said the toll from the eruption has risen to 15 with the death Saturday night of a severely burned victim.

Among the dead are 15-year-old Zoe Hosking from Australia and her stepfather, Gavin Dallow, 53. The first named victim was Krystal Browitt, a veterinary nursing student from Melbourne, Australia, who turned 21 on Nov. 29.

Police divers working in contaminated waters around White Island tried Saturday to find the remaining two victims.

Ash and other fallout from the eruption has made the sea near the island toxic, and divers have to be washed clean after every dive.

Tims called search conditions “unique and challenging.”

“Divers have reported seeing a number of dead fish and eels washed ashore and floating in the water. Conditions in the water today are not optimal, with between zero and two meters visibility depending on location,” he said.

Military specialists recovered six bodies from the island Friday in a carefully planned but risky operation. The two remaining bodies of victims known to have been on the island could not be found during the four-hour operation, carried out by bomb disposal experts — six men and two women — wearing yellow hazmat suits and breathing equipment.

Police think one of the missing bodies was sighted in the water close to the island by rescue teams Tuesday, the day after the eruption. The location of the other body is not known.

Divers began the search for the bodies Friday but were forced to stop near evening when the weather deteriorated. An aerial search of the island was suspended at nightfall.

The six bodies found Friday were transported to Auckland for identification.

In a statement, police said their own experts, forensic pathologists, scientists, odontologists and coroner’s officials were involved in the work of identification. Under New Zealand law, the coroner must confirm the victims’ identities.

Police said the process may take time, though they are working as quickly as possible to return the bodies to their families.

Prime Minister Jacinda Ardern called on New Zealanders to observe a minute’s silence in memory of victims at 2:11 p.m. Monday, exactly a week from the time of the eruption. Ardern and her Cabinet will pause in silence during their regular meeting at Parliament in Wellington.

“Wherever you are in New Zealand or around the world, this is a moment we can stand alongside those who have lost loved ones in this extraordinary tragedy,” Ardern said. “Together we can express our sorrow for those who have died and been hurt and our support for their grieving families and friends.”

The two last victims are believed to be New Zealanders — a tour guide and a boat captain who had taken tourists to the island.

The eruption Monday happened as 47 tourists and their guides were exploring the island.

Specialist medical teams were heading to New Zealand from Australia, Britain and the United States. Skin banks were also sending tissue to New Zealand hospitals to use for grafts.

Authorities say 24 Australians, nine Americans, five New Zealanders, four Germans, two Britons, two Chinese and a Malaysian were on the island at the time of the eruption. Many were from a Royal Caribbean cruise ship that had left Sydney two days earlier.