A volcano has erupted in New Zealand, leaving one dead and several unaccounted for, police have said.
Tourists were seen walking inside the rim of the White Island crater just moments before the eruption.
Police said 23 people had been rescued, but warned the number of dead was "likely" to rise. The area is currently too dangerous for a rescue operation.
White Island, also known as Whakaari, is one of the country's most active volcanoes.
Despite that, the island is a tourist destination with frequent day tours and scenic flights available.
What happened at the volcano?
The eruption of White Island began around 14:11 local time (01:11 GMT).
Visitor Michael Schade - who was on a boat leaving the island after a morning tour - filmed a thick plume of ash and smoke as the volcano erupted.
He told the BBC he was at the crater just 30 minutes before the eruption.
"It was still safe-ish but they were trying to limit the group sizes [of people visiting the volcano]."
Describing the eruption, he said: "We had just got on the boat...then someone pointed it out and we saw it. I was basically just shocked.
"The boat turned back and we grabbed some people that were waiting on the pier."
A live feed from the volcano showed a group of visitors inside the crater before images went dark.
Who was on the island?
New Zealand Prime Minister Jacinda Ardern said there were "a number" of tourists on or around the island, both from New Zealand and overseas.
"I know there will be a huge amount of concern and anxiety for those who have loved ones at the island at that time - and I can assure them police are doing everything they can," she said.
She said police had launched a search and rescue operation but falling ash was hampering attempts to get to the site.
Deputy police commissioner John Tims said "at this stage, it is too dangerous for police and rescue services to go to the island," adding that the island was "covered in ash and volcanic material".
"We continue to assess the conditions that would allow us to go on to the island... we are taking expert advice with regards to the safety of any rescue attempt."
Police initially said there were 100 people on or near the island, then later revised down the number to 50.
Some of the visitors are thought to be passengers from cruise ship Ovation of the Seas, owned by Royal Caribbean. It is currently at port in Tauranga, a coastal city near White Island.