A 73-year-old man from southwest Montana died Wednesday in Yellowstone National Park after losing his footing while fishing.

Yellowstone National Park spokesman Dan Hottle says the man was fishing in the Yellowstone River near the Nez Perce picnic ground in the Mud Volcano area when witnesses say he lost his footing in chest-deep water while attempting to cross the river and was carried approximately 200 yards downstream in the swift current.

Another visitor ran downstream and pulled the unconscious man ashore and initiated CPR. Park rangers and medical staff were notified and responded but were unable to revive the victim. Hottle says the cause of death remains under investigation, and his name is being withheld pending completion of notification of family members.