VIDEO: American trapped in Turkish cave sends hopeful message from 3,000 feet below

The experienced American cave researcher stranded in Turkey's third-deepest cave after becoming critically unwell sent a video message from more than 3,000 feet below the surface, while rescuers struggled to get him up to the top.

“The caving world is a really tight-knit group and it’s amazing to see how many people have responded on the surface,” Speleologist Mark Dickey said in the video shared by Turkey’s communications directorate.

Dickey, 40, who was exploring the Morca cave in southern Turkey's Taurus Mountains on Saturday when he fell unwell with gastrointestinal bleeding, said that the Turkish government's "quick response" to send down medical supplies "saved" his life.

“I was very close to the edge,” said Dickey, the chief of the Sussex County-based New Jersey Initial Response Team.

The Croton-on-Hudson homeowner said he was still not "healed on the inside" as he made his gratitude statement while standing.

The scientist said that it takes "a day or two" for "communication" between himself and the rescuers above to "get back and forth."

Due to broken phone lines installed in the tunnels, contact between ground-level rescuers and Dickey's location is currently being relayed by experienced cavers, which takes around eight hours for each trip.

The doctors involved in the worldwide rescue effort determined whether he had to be carried out on a stretcher or could go on his own.

So that Dickey and the rescue crews can rest on the way back, many bivouac stations are being set up.

Rescuers are widening the cave's passages for a safer evacuation, and they are also worried about the risk of falling rocks because of the construction.

Rescuers are concerned not only about the physical hardships Dickey may experience after being saved but also about the psychological effects that waiting patiently for a long time within the caverns may have on him.