A US pot-holer has died after being stuck upside-down in a cave in Utah for more than 24 hours.
John Jones, 26, was part of a group of 11 people who set out to explore the Nutty Putty caves, around 100km south of Salt Lake City, the capital of Utah.
Nearly three hours after the group had entered the caves on Tuesday evening, Jones became stuck in a feature inside Nutty Putty known as Bob's Push, the Utah County sheriff's office said.
"This feature is very tightly confined, being about 45cm wide and 25cm high," the sheriff's office said in a statement.
"Jones was positioned with his head downhill and was unable to move further into the cave. He was also unable to move back up the Bob's Push area," the statement said.
Nearly 100 rescuers using "large amounts of technical and heavy rescue equipment" worked around the clock to try to free Jones, who was trapped 46m underground and 213m from the entrance of the cave.
At one point, the rescuers "were able to extricate Jones from the area where he was stuck and raise him a short distance to a more level, yet still tightly confined, area," the sheriff's office said.
But an "equipment failure" caused Jones to fall back into the Bob's Push area in the same position in which he had been stuck.
Late Wednesday, Jones lost consciousness. Rescuers pronounced him dead shortly before midnight, the Utah County sheriff's office said.