An international team of at least 150 rescuers gathered at a Turkish cave Friday and prepared to try to bring out a U.S. explorer who fell ill nearly a week ago while exploring more than 1,000 meters underground.

Mark Dickey, 40, was exploring Morca Cave near Anamur, Turkey, in the Taurus Mountains with a team of about 12 others last Saturday when he fell ill with what was determined to be internal bleeding.

At a depth of 1,040 meters, Dickey was unable to climb out on his own. The Turkish Caving Federation said the team alerted the European Cave Rescue Association.

A Hungarian rescue team that includes a doctor reached Dickey this week, was able to get him medicine and blood infusions, and was monitoring him at a base camp.

Dickey appeared in a video message that the rescuers recorded and released Friday. He appeared to be in good spirits but said he “was not healed on the inside yet” and would need a lot of help climbing out of the cave.

The head of the Turkish search-and-rescue team, Recep Salci, told the Reuters news agency Friday that Dickey was stable enough to be moved but that the operation would likely take several days.

Salci said that getting to Dickey’s location involves many narrow passages and descents where a rope must be used. Some areas can be accessed only by crawling.

Salci said it takes a healthy caver 12 hours to get down to the location and 16 hours to climb up. He said some areas would require explosives to widen.

Salci said many of the operations were already being carried out.

In his video message, Dickey thanked the Turkish government and others who reached him initially with medical supplies, which he said saved his life. He also thanked the international community of cave explorers who have responded.

The European Cave Rescue Association said teams from Turkey, Bulgaria, Croatia, Hungary, Italy and Poland arrived at the scene over the course of the last week. How long the rescue mission will take depends on whether Dickey will require a stretcher on the way out, Werner Zegler, the association’s vice president, told VOA in an interview.

Zegler estimated that it would take three or four days if Dickey did not need a stretcher and up to two weeks if he did. According to Zegler, there were more than 100 rescuers on site. If initial extraction efforts fail, more might be necessary, he said.

Ivana Konstantinovic of VOA’s Serbian Service contributed to this report. Some information came from The Associated Press, Reuters and Agence France-Presse.