Rescuers from across Europe rushed to a cave in Turkey on Thursday, launching an operation to save an American researcher who became trapped around 1,000 metres below the surface after suffering stomach bleeding.

Experienced caver Mark Dickey, 40, suddenly became ill during an expedition with a handful of others, including three other Americans, in the Morca cave in southern Turkey’s Taurus Mountains, the European Association of Cave Rescuers said.

In a video message from inside the cave and made available Thursday by Turkey’s communications directorate, Mr Dickey thanked the caving community and the Turkish government for their efforts.

“Hi. Mark Dickey from nearly a thousand metres,” Mr Dickey said. “The caving world is a really tight-knit group and it’s amazing to see how many people have responded on the surface.

“We’re still waiting for communications actually to reach down here. So 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.”

Mr Dickey, who had been bleeding and losing fluid from his stomach, has stopped vomiting and has 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 is “very sick” and is located about 1,000 metres below the surface. The rescue will require many teams and constant medical care, the group said.

Communication with Mr Dickey takes about five to seven hours and is carried out by runners, who go from Mr Dickey to the camp below the surface where a telephone line to speak with the surface has been set up.

The New Jersey group says the cave is cold — about 4-6C.

Dinko Novosel, a Croatian cave rescuer who is head of the European Association of Cave Rescuers, said it will 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.

Mr Dickey experienced the gastrointestinal bleeding during his descent into the cave and he is unable to hoist himself out on his own, the European Cave Rescue Association said on its website.

The group described Mr Dickey 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. He is secretary of the association’s medical committee.

Experts say the rescue operation could take days or even weeks depending on conditions.

Mr Dickey was on an expedition mapping the 1,276-metre deep Morca cave system for the Anatolian Speleology Group Association (ASPEG) when he ran into trouble about 1,000 metres down, according to Yusuf Ogrenecek of the Speleological Federation of Turkey.