Polish rescuers said Monday they are still searching for two men who became trapped in a mountain cave last week when their corridor to the outside was flooded with water.

"We fear for their lives right now. We have no information as to whether they're alive. That's the key question," mountain rescue service chief Jan Krzysztof told reporters. 

The men had entered the Wielka Sniezna limestone cave in the Tatra mountains of southern Poland on Thursday along with four other spelunkers, who resurfaced and raised the alarm after losing contact with the pair on Saturday. 

Rescuers used explosives to try to clear a path towards the men trapped in the cave, which is the country's deepest and longest. 

Krzysztof said the search could take several days, adding that the men faced the risk of hypothermia because of the cave's low temperature.

Slovak rescuers, firemen and mining industry rescuers have also joined the search effort.