Eight people were missing and presumed dead on Tuesday after a volcanic eruption covered a small New Zealand island popular with tourists in hot ash and steam, killing five people and seriously injuring around 30 more.
Prime Minister Jacinda Ardern said aerial reconnaissance flights showed no signs of life on White Island, as eyewitnesses detailed the horrific burns suffered by some survivors.
Ardern said tourists from Australia, the United States, Britain, China and Malaysia were among the missing and injured, along with New Zealanders.
"To those who have lost or are missing family and friends, we share in your unfathomable grief in this moment at time and in your sorrow," Ardern said at a news conference in Whakatane, a town on the mainland's east coast, some 50 km (30 miles) from White Island.
A crater rim camera owned and operated by New Zealand's geological hazards agency GeoNet showed one group of people walking away from the rim inside the crater just a minute before the explosion. Other webcams showed the explosion that shot an ash plume some 12,000 feet (3,658 m) into the air.
"It's now clear that there were two groups on the island - those who were able to be evacuated and those who were close to the eruption," Ardern added.
Rescuers have been unable to access the island, which is covered in grey ash. GNS Science, New Zealand's geoscience agency, warned there was a 50/50 chance of another eruption in the coming 24 hours, as the volcano vent continued to emit "steam and mud jetting".
A New Zealand man, whose tour group was just leaving the island at the time of the eruption, said he helped pulled critically injured survivors into a boat.
Geoff Hopkins, 50, who was given the tour as a birthday gift, said many of the survivors had run into the sea to escape the eruption.
"They were just so massively burnt," he told the NZ Herald newspaper. "People were in shorts and T-shirts so there was a lot of exposed skin that was massively burnt."
Australian Prime Minister Scott Morrison said on Tuesday three Australians were feared to be among the confirmed fatalities, with 13 among the injured.
"I fear there is worse news to come," Morrison said.
Some 30 people were hospitalised, many with critical injuries, Ardern said, adding authorities were still assessing how close rescuers can get to the island.
"Ash is obviously significant," she said after visiting with first responders. "We’ve heard reports of one boat returning with up to half a metre of ash."
UK High Commissioner to NZ, Laura Clark, confirmed on Twitter that two British women were among the injured in hospital.
'A disaster waiting to happen'
'Whakaari', as it is known in the Maori language, is New Zealand’s most-active cone volcano, built up by continuous volcanic activity over the past 150,000 years, according to GeoNet.
About 70% of the island is under the sea, making the massive volcanic structure the largest in New Zealand.
Ray Cas, a professor emeritus at Monash University, said the island "has been a disaster waiting to happen for many years".
"Having visited it twice, I have always felt that it was too dangerous to allow the daily tour groups that visit the uninhabited island volcano by boat and helicopter," Cas said in comments published by the Australian Science Media Centre.
GeoNet raised the alert level for the volcano in November because of an increase in volcanic activity. The volcano's last fatal eruption was in 1914, when it killed 12 sulphur miners. There was a short-lived eruption in April 2016.
Yet daily tours bring more than 10,000 visitors to the volcano every year. One from a 16-deck cruise liner, Ovation of the Seas, was there at the time.
Royal Caribbean confirmed late on Monday that several passengers from the ship were on a day trip to the island but did not provide further information.
Janet Urey, 61, a nurse from Richmond, Virginia, said her son Matthew, 36, was injured in the eruption while on honeymoon.
"The phone rang at midnight. Then I heard a voicemail come on. It was my son. He said, 'Mom ... this is not a joke. A volcano erupted while we were on the island. We’re at the hospital with severe burns.'"
Urey said she was frustrated by the lack of information from the cruise ship he was on and from authorities.
"I have not heard a word from the cruise people," she said.