A seriously ill and trapped American stranded about 1000 metres under ground in a Turkish cave has issued an emotional video message to his rescuers.

A team of about 170 experts from across Europe has rushed to the Morca cave in southern Turkey’s Taurus Mountains to try to save 40-year-old Mark Dickey, who is suffering severe stomach bleeding and is unable to get to the surface on his own.

“Hi. Mark Dickey from nearly a thousand metres,” Mr Dickey said in the video message on Friday (Australian time).

“The caving world is a really tight-knit group and it’s amazing to see how many people have responded on the surface.”

Mr Dickey said he was still waiting for communications to reach the spot where he is camped.

“Right now, it’s a day or two days of travel for information to get back and forth. I don’t quite know what’s happened, but I do know that the quick response of the Turkish government to get the medical supplies that I need, in my opinion, saved my life. I was very close to the edge,” he said.

MrDickey suddenly became ill during an expedition with a handful of others, including three other Americans, in the deep and difficult Morca cave.

He has been bleeding and losing fluid from his stomach. More recently, he has stopped vomiting and had eaten for the first time in days, according to a New Jersey-based cave rescue group he is affiliated with.

It is unclear what caused his medical issue.

The New Jersey Initial Response Team said Mr Dickey was “very sick” and stuck about 1000 metres below the surface. The rescue would require many teams and constant medical care, it said.

Elsewhere, Yusuf Ogrenecek of the Speleological Federation of Turkey said Dickey’s condition had stabilised, and he was in “good spirits”.

“Mark’s condition continues to improve,” the federation tweeted.

“Doctors will decide whether it is possible for him to leave without a stretcher.”

A map of the Morca cave, showing where Mr Dickey is trapped. Image: European Cave Rescue Association

Communication with Mr Dickey takes about five to seven hours and is carried out by runners. They go from him to another below-ground camp, where a telephone line to speak with those above the ground has been set up.

The New Jersey group said the cave was cold – about 4-6 degrees.

Dinko Novosel, a Croatian cave rescuer who is head of the European Association of Cave Rescuers, said it would be a challenge to successfully rescue Mr Dickey.

The operation to bring him up from the depths involves rescue teams from Bulgaria, Croatia, Hungary, Italy, Poland and Turkey.

The association said Mr Dickey was unable to hoist himself out on his own, due to his gastrointestinal bleeding.

It described him as “a highly trained caver and a cave rescuer himself” who is well known as a cave researcher, or speleologist, from his participation in many international expeditions. Mr Dickey is secretary of the association’s medical committee.

Gretchen Baker, from the US National Cave Rescue Commission, who has known and worked with Mr Dickey for several years and has been in communication with the rescue team, was cautiously optimistic the rescue would be a success.

“The team on the ground is very happy that Mark’s condition seems to be improving, so that it looks like that he will not have to be in a [rescue] litter the entire way out,” she told CNN

“The more he can help, the faster the rescue can go,” she said.

But she said there was still some way to go.

“We’re anticipating that it will take days to get him out of the cave,” she said.

A rescue mission at such a depth is “very rare, extremely difficult” and needs “many very experienced cave rescuers”, the European Cave Rescue Association, which is involved in the operation, said.

Marton Kovacs of the Hungarian Cave Rescue Service said the cave was being prepared to bring Mr Dickey safely out. Narrow passages are being widened to accommodate a stretcher, while the danger of falling rocks is also being addressed.

The rescue teams, from Hungary, Bulgaria, Italy, Croatia and Poland, hope the extraction will begin on Saturday or Sunday.

-with AAP