New Zealand Prime Minister (PM) Jacinda Ardern has said there were no signs of life on White Island following a volcanic eruption.
She said the focus was now “on recovery” and “to return loved ones”, once the island was safe.
Thirteen people are presumed to have died, five of those are confirmed dead and eight are still missing on the island.
The volcano erupted on Monday as tourists were visiting the popular attraction.
Thirty-four people survived, with 31 still receiving treatment in hospital.
Among those hit by the eruption are people from New Zealand, Australia, China, Malaysia, the US and the UK, Ms Ardern said in a press conference on Tuesday.
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,” Ms Ardern said.
She said reconnaissance flights that day showed no signs of life on the volcanic island.
“The helicopter pilot, as I understand, physically moved around the island rather than just an aerial survey and did so for some time and so brought back that report that unfortunately there were no signs of life.”
Visitors from several countries as well as locals are among the missing and injured.
Police said a total of 47 people had been on the island when the disaster happened on Monday afternoon local time.
Two British women were among those receiving treatment, said the UK High Commissioner to New Zealand, Laura Clarke.
Australian Prime Minister Scott Morrison said he “feared” three of the five confirmed dead were Australian.
Mr Morrison said that 24 Australians were on board a cruise ship exploring the island in the Bay of Plenty when the volcano erupted. Of those, 13 people had been hospitalised and 11 were unaccounted for, he said.
“This is a terrible tragedy, a time of great innocence and joy interrupted by the horror of that eruption,” Mr Morrison told reporters in Sydney.
Ms Ardern acknowledged the apparently high number of Australian victims.
“Can I say to our Australian family, there are no two countries closer and we are devastated at what has happened here and particularly want to acknowledge those from Australia who have been caught up in this horrific, horrific incident,” she said.
What happened at the volcano?
White Island, also called Whakaari, is the country’s most active volcano. Despite that, the privately owned island is a tourist destination with frequent day tours and scenic flights available.
The volcano erupted in two explosions in quick succession at around 14:11 (01:11 GMT) on Monday, sending up a thick plume of ash and smoke.
A live feed from the volcano showed several visitors inside the crater before the stream went dark.
According to Ms Ardern, there were two groups on the island at the time, “those who were able to be evacuated and those who were close to the eruption”.
Some survivors were rescued by boat in the immediate aftermath of the explosion, but police said it was too dangerous to mount a rescue operation.
But later private helicopter rescue missions picked up several people from the island.
Speaking on Tuesday morning, Prime Minister Ardern paid tribute to helicopter crews who had flown to the island on Monday to bring people out despite the dangers.
“I want to acknowledge the courageous decision made by first responders and those pilots who in their immediate rescue efforts made an incredibly brave decision under extraordinarily dangerous circumstances in an attempt to get people out,” she said.
Since then, emergency services have been unable to search the area because of dangerous conditions, with plumes of smoke and ash continuing to rise above the volcano on Tuesday.