The incident highlights the coexistence challenges at one of the nation’s largest urban military installations, where up to 75 brown bears and 350 black bears roam a 100-square-mile training landscape shared daily by service members.

Two U.S. Army soldiers were injured Thursday after encountering a brown bear during a land navigation training exercise in Arctic Valley, a mountainous area within Joint Base Elmendorf-Richardson’s training grounds in Anchorage, the military said Friday.

The soldiers were receiving medical care as of Friday. Their conditions were not released pending notification of relatives. Both used pepper spray on the bear, a military official told the Anchorage Daily News. The incident remained under investigation Friday, and few additional details were available.

“The safety and well-being of our personnel is our highest priority,” Lt. Col. Jo Nederhoed, a spokesperson for the U.S. Army 11th Airborne Division, said in an email to the Anchorage Daily News.

Wildlife agency investigating

The Alaska Department of Fish and Game said it is investigating what it described as what appears to have been “a defensive attack” by a bear that had recently emerged from a den. Base officials closed the area near the incident to recreational activity after the encounter, the department said.

Investigators collected biological samples with the aim of positively identifying the species and gender of the bear involved.

A base shared with hundreds of bears

Joint Base Elmendorf-Richardson spans 100 square miles within the Municipality of Anchorage. The base is home to up to 350 black bears and 75 brown bears that roam its terrain freely, according to the Associated Press, making wildlife encounters an inherent risk for personnel conducting outdoor training.

Messages sent to base spokespersons by the Associated Press were not immediately returned Friday.