A 35-year-old man was attacked by a bear while hiking on a popular trail in Glacier National Park in Montana on Thursday morning, the National Park Service said.

The man was hiking with a group when they encountered a bear on the Highline Trail near the Grinnell Glacier Overlook trailhead, according to a news release from the Park Service.

After the attack, which the authorities did not describe, the man, who sustained non-life-threatening injuries, hiked over a mile in a mountainous area to Granite Park Chalet with the help of park rangers and other hikers, the Park Service said. He was then flown to the southwest edge of the park and taken by ambulance to a hospital in Whitefish, Mont., park officials said.

Glacier National Park rangers closed several miles of the Highline Trail after the attack. Park officials said they did not know whether the bear that attacked the man was a black bear or a grizzly bear.

Glacier National Park is home to nearly 1,000 bears, according to the Park Service. Park officials recommend that visitors hike in groups of four or more, if possible, to decrease the likelihood of an encounter with a bear. They also recommend keeping bear spray nearby while hiking and to make noise on the trails.

Bears are more likely to encounter people this time of year. During the fall, bears enter a phase called hyperphagia, during which they try to eat more and bulk up fat reserves before hibernating in the winter months.