A 77-year-old man from Australia died while swimming in the Colorado River at the Grand Canyon National Park, the park service said Thursday.

Park rangers responded to an emergency call of assistance on Tuesday for Kenneth Reece of Tasmania, Australia, who was on a river trip, according to the National Park Service. Reece was swimming in area around Deer Creek Falls, where other members of the river trip rescued him and attempted CPR.

Responding rangers took over when they reached River Mile 136 but were unable to resuscitate the man.

Reece's body was taken by helicopter to the Coconino County Medical Examiner Office, where an investigation into his death is taking place.

The National Park Service warned that swimming in the Colorado River is different than swimming in calmer bodies of water and that even strong swimmers can be overcome.

"The water can change in depth unexpectedly, going from shallow to deep in just a few steps, and it can have swift, strong currents, waterfalls, cold temperatures, and underwater hazards such as trees and boulders," the park service said.