An American couple spending their honeymoon on a cruise in New Zealand are among those who were seriously burned when a volcano erupted on an island filled with tourists on Monday, as the death toll keeps rising.

The New Zealand police said in a press release late Tuesday that a person who was being treated at the Middlemore Hospital after the White Island eruption has died, bringing the official death toll to six.

White Island sits about 30 miles offshore from mainland New Zealand and experts say it's the country's most active cone volcano, with about 70 percent of the volcano lying under the sea.

"Police remain focused on supporting families at this terrible time," the force said.

NEW ZEALAND VOLCANO ERUPTION LEAVES 'NO SIGNS OF LIFE' ON ISLAND

The New Zealand Police said that there were 47 people on the island at the time of the eruption, including 24 people from Australia, nine from the U.S., two from China, four from Germany, five people from New Zealand, two from the United Kingdom, and one person from Malaysia. Many were passengers aboard the Royal Caribbean cruise ship Ovation of the Seas.

Eight people who were reported missing are presumed dead, and bodies of the deceased are being transported to Auckland.

"We are working to confirm the identities of those involved, including those who have died and who are injured," police said, adding, "The nature of the injuries that people have suffered is severe and means identifying them is a complex matter."

Among the injured are American couple Matthew and Lauren Urey, from Richmond, Va., who were spending their honeymoon in New Zealand.

They spoke to family members just before heading to the island.

“She said they were going to the volcano,” Lauren’s mother, Barbara Barham, told The Washington Post. “My husband was joking around and said, ‘I hope it’s not a live volcano.’"

Relatives told WTVR-TV that Matthew left his family a voicemail informing them he and his wife were badly burned, and they were later contacted by Royal Caribbean.

Matthew sustained burns to around 80 percent of his body, while Lauren suffered burns to about 25 percent of her body and is facing surgery, family members told the television station. The family is now on the way to New Zealand to be with the "sweet couple."

Sylvain Plasse, a passenger on the Ovation of the Seas, said he saw the couple the night before in the cruise concierge lounge.

"It was his first cruise and it sounded like she had done a few and she said 'we're on our honeymoon and so we're going to do an excursion at every port stop'. And I mentioned to them this was my 105th cruise on Royals so we started talking, conversing and I didn't see them in the lounge last night and there were rumors that there were honeymoon couples on the island and you just showed me one of the news footage with their picture of their wedding and it confirmed that it was them," Plasse told New Zealand media. "You never know, your life changes in a moment so, life is short."

About 30 of the survivors remained hospitalized on Tuesday, many flown to burn units around the country. The first confirmed death was of a local man, Hayden Marshall-Inman, a guide who had shown tourists around the island.

Former Whakatane Mayor Tony Bonne said Marshall-Inman was a keen fisherman and well-liked. He was so kind, Bonne said, that he would often leave extra money at the grocery store for those he knew were struggling to pay.

Marshall-Inman's brother, who didn't want to be named, told the New Zealand Herald "he died doing what he loved."

Australian Prime Minister Scott Morrison said 11 Australians are unaccounted for and 13 were hospitalized. Three Australians were suspected to be among the initial five confirmed dead, he told reporters in Sydney. “I fear there is worse news to come,” Morrison said.

NEW ZEALAND VOLCANO ERUPTS, AT LEAST 5 DEAD, RESCUERS CAN'T ACCESS ISLAND

New Zealand's GeoNet seismic monitoring agency had raised the volcano's alert level on Nov. 18 from 1 to 2 on a scale where 5 represents a major eruption, noting an increase in sulfur dioxide gas, which originates from magma. It also said volcanic tremors had increased from weak to moderate strength. It raised the alert level to 4 for a time after Monday's eruption but lowered it to 3 as the activity subsided.

Many people are now questioning why tourists were still allowed to visit the island after seismic monitoring experts raised the volcano's alert level last month.

“These questions must be asked and they must be answered,” Prime Minister Jacinda Ardern said in Parliament.

New Zealand's Deputy Police Commissioner John Tims said Tuesday that police were opening a criminal investigation into the deaths that would accompany an investigation by health and safety regulators.

But hours later, police put out a statement saying that while they were investigating the deaths on behalf of the coroner, “To correct an earlier statement, it is too early to confirm whether there will also be a criminal investigation.”

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A few locals laid flowers Tuesday at a fence on the waterfront near where the rescue boats had returned with the injured.

White Island, also known by the indigenous Maori name Whakaari, is the tip of an undersea volcano about 30 miles off New Zealand's main North Island.

At least 10 people were killed on the island in 1914 when it was being mined for sulfur. Part of a crater wall collapsed and a landslide destroyed the miners' village and the mine itself. The island became a private scenic reserve in 1953, and daily tours allow more than 10,000 people to visit every year.

The Associated Press contributed to this report.