The death toll from the White Island volcanic eruption in New Zealand rose overnight while two British women are among the injured.
As many as 13 people are presumed to have died, including eight still missing on White Island.
Thirty-eight of the tourists visiting the island when disaster struck at 2.11pm local time on Monday were reported to be passengers and crew from Royal Caribbean International ship Ovation of the Seas.
Police said a total of 47 people had been on the island – a popular tourist attraction – at the time.
There were 24 visitors from Australia, nine from the US, five from New Zealand, four from Germany, two from China and one person from Malaysia.
A total of 27 people were taken to hospital with burns to a third of their bodies. Others are also suffering from inhalation burns.
Two British women were among those receiving treatment, according to Laura Clarke, the UK High Commissioner to New Zealand.
Royal Caribbean set up hotlines, including 0800-014-8339 in the UK, for those concerned about relatives travelling on board Ovation of the Seas.
Australian Prime Minister Scott Morrison said he “feared” three of the five confirmed dead were from Australia.
He said that 24 Australians were from 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 added.
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,” according to New Zealand prime minister Jacinda Ardern.
Some survivors were rescued by boat in the immediate aftermath, but police said it was too dangerous to mount a rescue operation.
Helicopter rescue flights later picked up several people from the privately-owned island, 30 miles off the coast of New Zealand’s North Island.
Ovation of the Seas had been docked at Tauranga, a coastal city near White Island.
Royal Caribbean said: “The news from White Island is devastating. The details that are emerging are heartbreaking.
“We are working to help our guests and the authorities in the aftermath of this tragedy in any way we can.
“We are communicating with our guests and their families. We’re making sure they are taken care of in terms of medical help, counselling, accommodations, and transport. Our hearts go out to them, and we want to be as supportive as we can.
“Staff from our Sydney and Auckland offices office are already on-site, and we’re going to be offering all our resources while this terrible tragedy sorts out.
“We are grateful for the work of all the first responders and medical personnel. We also thank the prime minister and her team, the local authorities and everyone who has reached out to help with their kind thoughts and prayers.”
Ovation of the Seas was on a 12-day itinerary which left Sydney last Wednesday.
White Island, or Whakaari is one of New Zealand’s most active volcanoes yet attracts frequent day trips and scenic flights.
In updated travel advice, the FCO said: “The Whakaari/White Island volcano erupted on 9 December. An emergency response is under way. If you are travelling in the area, you should follow the advice of the local authorities and/or your tour operator.
“If you’ve been affected by the incident and need urgent consular assistance, you should contact the British High Commission in Wellington on +64 (0) 4 924 2888.
“If you are in the UK and you’re concerned about friends or relatives in the area, you should contact the FCO in London on 020 7008 1500.”
Around 200,000 British nationals visit New Zealand every year.