A kayaker’s leg was amputated during a dramatic, hours-long rescue operation to free him from between rocks on a river in Australia on Saturday, local police said.

The man, a foreign tourist in his 60s, was airlifted to a hospital in Tasmania’s state capital Hobart where he was in a critical condition, police said, adding they were contacting his family.

His 20-hour ordeal began at about 2:30pm on Friday when he became trapped while kayaking through rapids with a group on the Franklin River, police said in a statement.

Authorities received an emergency alert from the man’s smartwatch and dispatched rescue units and paramedics, police said, adding that the area’s remoteness added complexity to the rescue effort.

Set in the rugged landscape of the Franklin-Gordon Wild Rivers National Park in the island state, the powerful 129-kilometer- (80-mile-) long river is a popular spot for kayaking and rafting.

Rescuers made several unsuccessful attempts to extract the man between Friday evening and Saturday morning. When his condition deteriorated after so many hours partially submerged in the water, a decision was made in consultation with the man to amputate his leg, police said.

“This rescue was an extremely challenging and technical operation, and an incredible effort over many hours to save the man’s life,” said Tasmania Police Acting Assistant Commissioner Doug Oosterloo in the statement.

“Every effort was made to extract the man before the difficult decision to amputate his leg.”

Oosterloo also praised the emergency responders. “I’d like to thank everyone who contributed to this operation in the most difficult of circumstances,” he said.