Swiss police say eight men who have been stuck in a cave in the Alps since Saturday will likely have to spend at least another 48 hours underground because of flooding.

The group, including a qualified guide, entered the Hoelloch cave in the Muotathal valley in central Switzerland on Saturday morning on what was supposed to be a two-day expedition.

The men, aged 25 to 55, were unable to leave the cave on Sunday because of an inrush of water. They are waiting in a bivouac that is secure from flooding.

Schwyz canton (police) said Monday that the men are all unhurt.

Organizers had expected snow but it rained instead, and water in the cave rose quickly.