Updated at 4:54 a.m. ET Sunday

New Zealand police said they were unable to find two remaining bodies in a search Sunday for victims killed in a volcanic eruption on White Island, while the death toll rose to 16 after another person died in a hospital.

Police said eight specialists searched an area of the island Sunday where they believed a body would be located.

"While it is frustrating not to have located the remaining two bodies, I'd like to reiterate our commitment to doing all we can to provide a sense of closure to the grieving families," said Deputy Commissioner John Tims.

He said the two remaining bodies are most likely in the water, but authorities wanted to be sure.

Tims said divers searched the water off the island Sunday as well, and divers will be searching again Monday dependent on weather conditions.

Separately, New Zealand's police said a 16th victim who had been transported to a hospital in Australia died on Saturday.

Tims said the divers' search for remaining bodies is a "difficult and ongoing task" — especially because of the poor water quality. The water is contaminated because of the eruption and visibility is limited — 6.5 feet or fewer, according to a police statement.

"Divers have reported seeing a number of dead fish and eels washed ashore and floating in the water," Tims said earlier. "Each time they surface, the divers are decontaminated using fresh water."

The divers are also operating under the threat of another eruption. GeoNet, which monitors volcanic activity in New Zealand, estimated on Saturday that there is a 35% to 50% chance of another eruption on the island in the next 24 hours. That's a decrease from Friday, when the experts estimated a 50% to 60% likelihood of an eruption in the next day.

Authorities were able to recover six bodies from the island on Friday, meaning that two people remained unaccounted for.

Col. Rian McKinstry from the New Zealand Defence Force told Stuff that on Friday, the recovery team used hazmat suits with a special protective layer containing charcoal to filter out noxious gases. The team also used oxygen masks.

When the volcano on White Island, also known by its Maori name, Whakaari, erupted on Monday afternoon, 47 people — many of them tourists from around the world — were there exploring. Some of the survivors are suffering from major burns to their skin and lungs. Major questions persist about why so many people were freely wandering around in an area that was known to be an active volcano.

Police formally identified the first victim of the eruption on Saturday – Krystal Eve Browitt, a 21-year-old Australian citizen. The young woman had been on a cruise with her parents and sister, according to The Sydney Morning Herald. Her mother had stayed behind on the cruise, and her other two family members are believed to be receiving treatment for their injuries in an Australian hospital.

Browitt's principal from Kolbe Catholic College, Nick Scully, says that she was a "much-loved member of the Kolbe community that her teachers describe as a beautiful soul," the Herald reported.

The 15th fatality from the eruption, which police confirmed Saturday, was a person who had been being treated for injuries at a hospital in New Zealand.

New Zealand Prime Minister Jacinda Ardern has called for a minute of silence on Monday at exactly a week after the eruption started.

"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 in a statement. "Together we can express our sorrow for those who have died and been hurt, and our support for their grieving families and friends."

As NPR's Colin Dwyer reported, of the 47 people who were on the island at the time, 24 were from Australia and nine from the U.S. Others were from China, Malaysia, Germany, the U.K. and New Zealand.

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