More than two dozen rescue workers are battling to save two cavers trapped in a cavern in Poland's Tatra mountains after a narrow tunnel flooded with water, blocking their exit.
A representative of the mountain rescue service says it has not yet been possible to establish contact with the two cavers and concern was growing due to their long exposure to extreme conditions.
Rescuers were preparing to use explosives to open a route to access the two but the process would not be quick.
"The only way to get to them is through a series of very complicated pyrotechnic actions," said Jan Krzysztof, head of the Tatra Volunteer Search and Rescue group, in an impromptu interview broadcast by TVN on Sunday.
"We have the necessary materials but this will take a long time," Krzysztof said. "We have to be ready for work that could last days, if not weeks."
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The two became trapped in the Wielka Sniezna cave, the longest and deepest in the Tatra mountains, on Saturday and rescue services were notified by colleagues who had accompanied them on the excursion, TVN reported.
The first rescue group was sent in on Saturday evening and since then two more groups, including workers from the fire department in Krakow, had been dispatched, TVN said.
Additional support could come from Slovak rescuers, Krzysztof told reporters.
Rescue conditions were particularly difficult because of flooding which could also endanger the rescuers, TVN reported.