A young man reportedly was seen Tuesday falling into a hot spring in the Norris Geyser Basin in Yellowstone National Park/Kurt Repanshek file photo

A young man in his early 20s reportedly was seen falling into a hot spring in the Norris Geyser Basin in Yellowstone National Park on Tuesday.

Park officials said the matter was being treated as a "probable fatality because the victim has not been located." Rangers were using "extreme caution" searching for the man's remains due to the dangers of the thermal area, which can include thin surface crusts that easily collapse into boiling waters. The Norris Geyser Basin is the hottest thermal area in Yellowstone.

A park release Tuesday evening said the location of the incident was approximately 225 yards off one of the boardwalk. The release did not specify which hot spring in the Norris Basin was involved.

The Norris Geyser Basin was closed to the public following the witness's report, and no further information was expected Tuesday night.