Rescue services were working to reach the stranded trio on Friday.
Rescuers in Austria are working to save three Polish researchers who became trapped by water inside a cave.
Officials in Salzburg said a rescue operation was launched late on Thursday in the Lamprechtsofen cave near the village of St. Martin bei Lofer.
Unusually warm temperatures caused melted ice or snow to enter the cave where the researchers were collecting rock samples, the authorities said.
A diver has been to reach the three people who "appear to be well, but are suffering from hypothermia".
“We are optimistic because the explorers are well equipped, as full professionals they can handle the situation and there are rescue niches with blankets as well as emergency equipment in the cave,” said Monika Feichtner, head of Salzburg’s cave rescue service.
She added that officials hope the water will recede in colder weather and lower temperatures.
The Lamprechtshöhle cave complex stretches for 60 kilometres and is one of the deepest caves in the world.