The evacuation of an experienced American caver and researcher who fell ill more than 3,000 feet below the entrance of a cave in Turkey has begun, according to the New Jersey Initial Response Team, the organization he works with.

Turkish officials announced Friday that Mark Dickey, 40, had recovered sufficiently enough to be extracted in an operation that could last three or four days.

Rescuers from across Europe have rushed to the cave for an operation to save Dickey, who became suddenly ill with stomach bleeding during an expedition with a handful of others in the Morca cave in southern Turkey's Taurus Mountains.

"The doctors we sent down were very successful in treating him," Cenk Yildiz, a regional official from Turkey's disaster relief agency, told the IHA news agency. "We are now in a position to evacuate him."

"This is a difficult operation. It would take a (healthy) person 16 hours to come out. This operation will last at least three or four days," Yildiz continued. "Our priority is health. Our aim is to conclude this operation without anyone coming under any danger."

More than 170 people, including doctors, paramedics and experienced cavers, are involved in the rescue operation.

The European Cave Rescue Association said Saturday that Dickey's medical status was stable. A blood analysis device has been delivered to him to enable blood testing.

"Preparations are being made on the stretcher evacuation route to a further bivouac prepared at -700 m," the statement said.

The cave was being prepared for Dickey's safe extraction, including passages being widened and the danger of falling rocks being addressed, according to the Hungarian Cave Rescue Service and other officials.

"Patient Mark Dickey is being moved towards the entrance. This is a very difficult, deep and muddy cave. Some of the vertical climbing gear used by rescue cavers is wearing out and needs to be replaced," Carl Heitmeyer, public information officer for the New Jersey Initial Response Team, said Saturday.

Dickey fell ill on Aug. 31 while on an exploration of the Morca cave and has been unable to return to the surface, according to the New Jersey Initial Response Team. Dickey is the chief of the group, which specializes in cave and mine rescue, as well as an instructor for the National Cave Rescue Commission.

The expert caver was helping lead an international caving expedition when he started suffering intestinal problems "that rapidly progressed into life-threatening bleeding and vomiting," the New Jersey Initial Response Team said in a statement.