Rescuers searching for five men who have been trapped inside a Virginia cave since Saturday night are settling in for what could be a long operation to bring them out safely.

"With cave rescue incidents, this has the chance to extend to eight to 12 hours," Virginia Department Search and Rescue Coordinator Billy Grimes told WJHL.

The trapped men, ranging in age from 35 to 59, are believed to be uninjured inside Cyclops Cave, according to Russell County Emergency Management.

Although the cave in southwestern Virginia has more than seven miles of passages in it, some of which are quite narrow, authorities believe the men are not in the cave's farthest reaches.

Emergency personnel are on standby as rescue crews rappel down into the cave.

"It will take some time to get good information back," Grimes said at an afternoon press briefing.

The man had been planning to spend Saturday night inside the cave until it started to rain at 11 p.m., which made the rock walls slippery and therefore difficult to climb.

CLICK HERE TO GET THE FOX NEWS APP

Russell County Emergency Management said the trapped men are tired, hypothermic and unable to climb out of the cave.

A sixth man, 22, was able to escape and call 911.

This is a developing story. Check back for updates.