Rescue teams on Sunday in Turkey successfully carried an American researcher up from the depth of a cave at 1,040 meters (3,410 feet) to the 700-meter mark where he will rest at a base camp before they continue the taxing journey to the surface.

An experienced caver, Mark Dickey, 40, started vomiting on Sept. 2 because of stomach bleeding while on an expedition with a handful of others in the Morca cave in southern Turkey’s Taurus Mountains, one of the deepest in the world, according to experts.

A rescue operation began Saturday afternoon with doctors, paramedics and experienced cavers from across Europe rushing to help. They set up small medical base camps at various levels along the shaft, providing Dickey an opportunity to rest during the slow and arduous extrication.

“Mark was delivered to the campsite at -700 meters as of 03:24 local time (GMT+3). At this stage, he will set out again after resting and having the necessary treatments,” the Speleological Federation of Turkey wrote on its official account on X, formerly known as Twitter.

Turkish authorities said there are 190 personnel from eight countries taking part in the operation, 153 of them search and rescue experts.

The most challenging part of the rescue operation is widening the narrow cave passages to allow stretcher lines to pass through at low depths, Yusuf Ogrenecek of the speleological federation previously said.

The extraction is expected to take up to 10 days depending on his condition.