LONDON -- The American caver trapped underground in Turkey has been hoisted to safety.

Mark Dickey, 40, had been trapped underground since Aug. 31, when he fell ill more than 3,400 feet below the surface, according to the New Jersey Initial Response Team, a group he leads.

Dickey was extracted from the cave around 12:37 a.m. local time on Tuesday, the Turkish Caving Federation announced, describing the operation as "successful."

"We congratulate all those who contributed!" the caving organization said.

Video taken from the scene showed Dickey lying on a stretcher as he was lifted through the cave 12 days after he became trapped.

A rescue team carried Dickey on a stretcher passed through a rest camp about 1,000 feet underground, international caving officials said on Monday. They rested in the area around the last 180 meters before he was pulled out.

A team that includes medical staff began an evacuation late last week, after his condition improved enough to move him, caving officials said. Volunteers have been working to clear a path to the surface for the past five days.

When the Hungarian Cave Rescue Service arrived on Sunday, Dickey was in serious, life-threatening condition, officials said. Life-saving medical intervention included high doses of medication for his stomach and a blood transfusion.

Dickey's condition improved enough for him to return to his feet following the intervention, rescuers said.

The team carrying the stretcher had passed a bivouac site about 500 meters, or 1,640 feet, below the surface about 12 hours earlier, the European Cave Rescue Association said.

"The medical status of the casualty is stable," the association had said in a statement on Sunday evening. "The next planned stop is at -300 m. The members of the different rescue teams are in a good physical condition."

"He has not had any bleeding or vomiting for at least 2 days," Sener said in a statement posted in Turkish on social media. "All vital signs, pulse, blood pressure, body temperature, state of consciousness, cooperation are all completely healthy."

Dickey had been assisting in the exploration of the cave when he "suddenly became ill with intestinal problems that rapidly progressed into life-threatening bleeding and vomiting," the New Jersey Initial Response Team said in a statement announcing the his situation. Dickey serves as the leader of that group, a collection of volunteers who specialize in cave and mine rescues.