Rescuers said on Monday they were only hours away from pulling to safety a US explorer trapped for more than a week, and suffering from gastrointestinal bleeding, deep in a Turkish cave.
Mark Dickey, 40, developed stomach problems on September 2 while examining the depths of the Morca Cave, a remote complex of narrow underground tunnels in southern Turkey's Taurus Mountains.
The Morca Cave is Turkey's third-deepest, its lowest point reaching nearly 1.3 kilometres (0.8 miles) below ground.
Dickey fell ill at a depth of 1,120 metres (695 feet), sparking what organisers said was one of the largest and most complicated underground rescue operations ever mounted.
An international team of rescuers, fellow explorers and medics began to cautiously pull Dickey to safety after first giving him infusions of blood.
He has been strapped to a stretcher, which sometimes needed to be lifted vertically by rope through particularly narrow passageways.
"Mark is in the last 100 metres," the Turkish Caving Federation said.
"Crews continue to work to have him out tonight."
Officials said Dickey's health has been steadily improving for a few days.
"He is in good health in general. He continues to be fed with liquids," Cenk Yildiz, the head of the local branch of Turkey's emergency response service, told reporters late on Sunday.
"We have resolved his stomach bleeding issues with plasma and serum support."
In a video recorded on Wednesday, Dickey thanked the Turkish government for its help.
"The quick response of the Turkish government to get the medical supplies that I needed, in my opinion saved my life," Dickey said.
The European Cave Rescue Association (ECRA) called Dickey an experienced explorer with a medical background.
The New York state native is a "well-known figure in the international speleological community, a highly trained caver, and a cave rescuer himself," the ECRA said.
"In addition to his activities as a speleologist, he is also the secretary of the ECRA medical committee and an instructor for cave rescue organisations in the USA."