The rescue of an American man trapped more than 3,000 feet deep in a Turkish cave could take days because the cave is so narrow, officials said

• An American man is trapped in a narrow Turkish cave at a depth of around 3,000 feet.
• Mark Dickey became ill during an exploration mission, and rescuers have been working to save him since Monday.

An American man is trapped over 3,000 feet deep in a Turkish cave — and officials say it could take days to rescue him.

Mark Dickey, 40, fell ill during an exploration and research mission in the Morca Sinkhole in the Morca Valley, the Turkish Caving Federation said earlier this week, and was placed under observation at a base camp.

Dickey had gastrointestinal bleeding, according to the Hungarian Cave Rescue Service, which was rushed to the cave to help. Since then, Dickey has received six units of blood and his condition has stabilized, but he can't get out of the cave on his own, officials said.

Teams are setting up rope lines to retrieve him. On Thursday, the federation said doctors are deciding if and when Dickey will be able to walk without a stretcher.

But Bulent Genc, head of the Turkish Caving Federation, told CNN on Thursday that rescue operations could take days due to the depth Dickey is at and the narrowness of the cave.

The Morca Sinkhole is the third deepest cave in Turkey. From Dickey's current location, it would take an experienced cave explorer about 15 hours to reach the surface due to Morca's narrow, winding passages and rappels, officials said.

A map from the federation shows the layout of the Morca Sinkhole. Dickey is currently stuck at the Hope camp that's 1,040 meters — or 3,412 feet — from the surface.

According to an online fundraiser for the rescue teams, Dickey is a "well-known figure" in the international caving community.

Dickey is also a cave rescuer himself and teaches how to save others at cave rescue organizations in the US.

Over 150 rescuers are involved in the operation, which the federation called "logistically and technically one of the largest cave rescues in the world."