Two people drove themselves to a nearby emergency room after being attacked by a brown bear while hiking along the two-mile Exit Glacier Trail in Seward, Alaska.

According to a news release from Alaska State Troopers, the incident happened on Wednesday, September 24.

Alaska State Troopers say they received a report from a local hospital just after 9 P.M., after the duo was admitted to the emergency room.

“Both individuals had to fight off the bear and sustained non-life-threatening injuries,” wrote Alaska State Troopers.

The incident occurred within the boundaries of Kenai Fjords National Park, renowned for its glaciers and diverse wildlife.

There is no cell service in Kenai Fjords National Park. Following the attack, the two hikers, who reportedly suffered non-life-threatening injuries, were in stable condition.

Officials told Outside that local biologists and Alaska Wildlife Troopers returned to the area the following day to find DNA evidence that could be used to identify the bear, but were unable to find any, Jeff Selinger, management coordinator with the Alaska Department of Fish and Game, told Outside in an email. Authorities do not know what prompted the attack.

Following the attack, the Kenai Fjords National Park Superintendent and local Alaska State Troopers closed the trail and surrounding areas. It’s unclear when the trails will reopen to the public.

“This incident remains under investigation in collaboration with Alaska State Troopers and Alaska Department of Fish and Game. There are no further details to share at this time,” wrote the National Park Service in a press statement.

In an interview with the Kenai Peninsula public radio station KDLL, Selinger said that determining the motivation of a bear attack helps to inform how authorities handle a bear if it’s caught.

“One of the big things we try to determine, and you know, it’s not always possible, is whether it was a defensive attack by the bear, for example, a sow protecting cubs, or if it’s a predatory attack, where you know the bear is attacking the person you know looking at them as—to consume them,” he told KDLL.

In a defensive attack, for example, authorities may hang signs to warn people of a potentially violent animal. In some rare instances, the bear may be euthanized.

The Exit Glacier area is home to a network of trails that lead to views of the glacier. Bears and moose frequently inhabit the area surrounding the hiking trails, and wildlife officials remind visitors always to practice bear safety.

“Be bear aware to help avoid surprise bear encounters. Kenai Fjords National Park recommends carrying bear spray and knowing how to use it,” wrote NPS.

The most accessible glacier on the Kenai Peninsula, Exit Glacier is the only part of Kenai Fjords National Park where visitors can drive to the trailhead—and only during the summer.

Bears are typically most active in the fall months when they undergo hyperphagia, consuming an enormous amount of calories in preparation for their winter hibernation.