5 people trapped in Virginia cave rescued: Officials The men planned to spend the weekend inside the cave, officials said.

A group of men who became stuck in a cave in Virginia after rain made it difficult to get out have been rescued, officials said Sunday.

A group of six initially planned to spend the weekend inside the cave in Cleveland, Virginia, until it began raining late Saturday night, Jess Powers, coordinator for the Russell County Emergency Management, told ABC News. The rain caused the ground inside the cave to become slippery, making it difficult for the men to get out, Powers said.

One person managed to escape, but the other five remained trapped in the cave, he added.

Only seven miles of the extensive cave have been mapped out, and the rescue could take up to 12 hours, Billy Chrimes, search-and-rescue coordinator for the Virginia Department of Emergency Management, told reporters Sunday morning. Rescuers have reached the men and it doesn't appear that they are too far into the cave, he added.

The first person was extracted from the cave before 4 p.m. Sunday, Jeff Stern, the state coordinator for the Virginia Department of Emergency Management, announced on Twitter. Another person was rescued after 5 p.m., Stern tweeted.

Three more people had been rescued before 6 p.m., Chrimes said, adding that everyone was taken to the hospital for observation.

The men had been inside the cave since Friday around 7 p.m., Chrimes said. They were not prepared for the rain after entering the cave, and did not bring enough food and water to last a sustained period of time, Chrimes said.

But rescuers have provided water to them, he added.

Crews had to assess how to conduct the rescue within the tight crevice at the entrance of the cave, Chrimes said. Rope-climbing and repelling were required to get through the drop at the entrance of the cave.

Temperatures underground are in the mid-50s, which poses the risk for hypothermia, officials said. The person who escaped told officials that others were feeling weak and experiencing signs of hypothermia, Chrimes said, adding that cell phones and radios do not work inside.

ABC News' Joshua Hoyos and Will Gretsky contributed to this report.