(MYSTIC FALLS, Wyo.) -- Two hikers were injured in a bear attack at Yellowstone National Park, prompting some areas of the park to close, the National Park Service said.

The incident occurred Monday afternoon on the Mystic Falls Trail near Old Faithful in Wyoming, the park service said. 

The two hikers "sustained injuries by one or more bears," the park service said in a press release on Tuesday.  

National Park Service emergency services personnel responded, and the incident remains under investigation, the park service said. 

The National Park Service did not release any additional details, including the condition of the hikers or the type of bear suspected in the attack.

Craig Lerman, a hiker from Maryland, told ABC News he noticed at least two sets of claw marks, a bloody hat and a watch near Mystic Falls before coming upon one of the victims on the trail yelling for help.

"I've never seen anything like that," Lerman said. "It's not something you ever want to walk up to. Obviously, it was bad."

He said the victim had wounds to his face, back and legs. Lerman said he gave the hiker his shirt and kept him company before first responders arrived and the victim was airlifted from the area.

Lerman said he believes the man's younger brother was the other hiker injured.

"I just hope that they both make it," he said.

Some areas of the national park are temporarily closed due to the ongoing investigation. 

The last bear attack in Yellowstone was in September 2025, when a 29-year-old man was injured by a grizzly bear while hiking alone near Turbid Lake.

The last deadly bear attack occurred in 2015, in the Lake Village area of Yellowstone, the park service said. 

ABC News' Tia Humphries, Bonnie Mclean and Chris Looft contributed to this report.

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