At least five people are dead, eight are reported missing and authorities are fearing the worst after a volcano erupted Monday at a popular tourist site in New Zealand.

Several dozen visitors, including some from a Royal Caribbean cruise ship, were on or near White Island when it erupted at 2:11 p.m. local time, releasing thick clouds of ash about 12,000 feet into the air. More than 30 people were hospitalized after being rescued, some with serious burn injuries.

Police do not believe there are any survivors among the missing, following what scientists called a “throat-clearing kind of eruption.” National police said early Tuesday that reconnaissance flights over the island found “no signs of life at any point.”

“Police believe that anyone who could have been taken from the island alive was rescued at the time of the evacuation,” authorities said in a statement. “Based on the information we have, we do not believe there are any survivors on the island.”

Prime Minister Jacinda Ardern said at a news conference that both New Zealanders and foreign visitors were on or around the island in the Bay of Plenty when the volcano erupted. White Island, which bills itself as “New Zealand’s most active volcano,” is uninhabited but frequented by tourists.

“I know there will be a huge amount of concern and anxiety for those who have loved ones on or around the island at the time, and I can assure them police are doing everything they can,” Ardern said.

The prime minister said it is “a very unpredictable volcano.”

As recovery operations continued Tuesday, police announced that they will be launching a criminal investigation into the incident, the Associated Press reported. At a news conference, Judy Turner, mayor of Whakatane, one of the mainland towns closest to White Island, said the investigation is “a natural process that would need to happen in these circumstances.”

“Everybody wants to make sure that there’s nothing untoward that’s contributed to this, and so we welcome that," Turner said.

When Lauren Urey called her parents Monday, the 32-year-old newlywed was excited. The Royal Caribbean cruise ship on which Lauren and her husband, Matthew, were spending their honeymoon had just docked in Tauranga, New Zealand, and the Richmond couple had an action-packed day ahead of them.

“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.’ ”

Actually, Lauren responded, it is. The Ureys had plans to visit White Island, but Lauren and Matthew, 36, “weren’t concerned that there was any chance of an eruption,” Barham said.

The couple were rushed to a hospital with severe burn injuries, Barham said.

A number of visitors to the island during the eruption came from the Ureys’ cruise ship, the Ovation of the Seas, which offered an excursion to the volcano. In a statement, New Zealand Cruise Association CEO Kevin O’Sullivan extended “heartfelt concern to the passengers and their families.”

Photos of the volcano’s crater rim minutes before the eruption showed people walking nearby, the New Zealand Herald reported.

One video taken of the eruption from a boat offshore captured thick clouds rising from the island. A voice could be heard frantically telling passengers to go inside the boat’s cabin. In another clip, the island appeared to be completely enveloped by ash.

New Zealand’s National Emergency Management Agency warned Monday on Twitter that it was “hazardous in the immediate vicinity of the volcano” and urged people to pay attention to detailed safety advice, adding: “Act on it promptly.”

The same dangerous conditions prevented police and rescue services from reaching the island, New Zealand Police Deputy Commissioner John Tims said, with experts warning that more eruptions are possible.

Barham told The Post that she and her husband, who live southeast of Richmond, had no idea that chaos was unfolding halfway around the world — and that their daughter was involved. Then, Barham said, she got a call from Royal Caribbean shortly after midnight Monday Eastern time asking whether she had heard from Lauren. The newlyweds hadn’t returned to their cruise ship after the volcano tour and were missing.

Soon, Barham’s phone was ringing again. It was Matthew’s mother, and she had just received a distressing voice mail from him.

“Her son called and said that they had been on the excursion and there had been a volcano eruption and they were burned very bad,” Barham said. “He said he would try to call as soon as he could, but talking and making phone calls was difficult. His hands were so badly burned, it was hard for him to make a phone call.”

In the voice mail, according to Barham, Matthew said he and Lauren, who also suffered similar injuries, had been taken to a hospital.

“Obviously, I’m panicking,” she said. “I don’t know how to act. I feel like I should be crying, but I can’t even cry.”

But as Barham tuned in to news coverage about the eruption, the shock began to give way to anger. Experts had reported increased volcanic activity on the island weeks before Monday’s incident.

“I’m just livid,” she said. “There’s been warnings about it. … My son-in-law never would have booked the excursion if he knew there was any chance of them being injured.”

A hospital representative later called Barham while Lauren was in surgery. The new bride has severe burns on her lower extremities, covering at least 20 percent of her body. She’s recovering at an Auckland hospital.

Matthew was airlifted to a hospital in Christchurch for treatment of burns that cover about 80 percent of his body, Barham said as she was preparing to fly out of Dulles International Airport on Monday night.

Matthew’s mom is making arrangements to see her son by week’s end, Barham said.

GeoNet, an agency that provides geological hazard information for New Zealand, had issued multiple reports of “volcanic unrest” on the island, going as far back as late October.

“Moderate volcanic unrest continues at Whakaari/White Island, with substantial gas, steam and mud bursts observed at the vent located at the back of the crater lake,” stated a report from last Tuesday.

The volcano was suspected to be entering a period in which eruptive activity was more likely than normal, according to the report.

White Island had a “short-lived eruption” in April 2016. Five months later, it emitted ash from a vent on the 2012 lava dome.

Monday’s eruption was surprising but not unique, according to scientist Ken Gledhill from GeoNet.

“In the scheme of things, for volcanic eruptions, it is not large,” he told the Associated Press. “But if you were close to that, it is not good.”

Tour operators make the final decision about whether to take visitors to the privately owned island, where access is controlled through permits, the New Zealand Herald reported.

During the news conference, Ardern declined to answer a question about whether visitors should have been allowed to go to the island.

“In this moment in time, the absolute focus needs to be the search-and-rescue operation,” she said. “There will be a time and a place to undertake further assessments. Now, we have to focus on allowing the police to do their job and focus on those who were in the vicinity of the island at the time.”

Royal Caribbean Cruises said in a statement that the company is “devastated.”

“We are working together with local authorities, and we are providing all the help and care we can to our guests and their families, including offering medical resources and counseling,” the company said.

Royal Caribbean is sending staff from the ship and its Sydney and Auckland offices to help family members. Ovation of the Seas will remain in port for the time being, the company said.

Emanuel Stoakes in Christchurch, New Zealand, contributed to this report.