Two victims are in critical condition and two others are in serious condition, the Canadian Press reported. Emergency services did not specify the ages of those injured following a bear attack.

The incident occurred early Thursday afternoon on a trail in the Bella Coola area, about 700 kilometers northwest of Vancouver. The mother of a 10-year-old boy, cited by the Canadian Press, said her son came so close to the animal that “he could feel its fur.” He then “ran for his life.” One of the teachers accompanying the group suffered the most serious injuries while trying to intervene, the boy’s mother, Veronica Schooner, added. The teacher was airlifted to a hospital.

Nuxalk emergency response services described the animal as an “aggressive bear.” As of Thursday night, the bear had not been located.

The Nuxalk Nation urged caution in posts on social media, asking residents to stay indoors and avoid the highway. The students were attending Acwsalcta School, an independent educational institution. “It is difficult to find the right words at such a painful moment,” the school said in a Facebook post.

“We are devastated for the individuals and families affected by the bear incident. Everyone involved is receiving medical support, and our priority is ensuring their safety,” said Nuxalk Nation Chief Samuel Schooner in a statement.

Bears are known to be especially aggressive during this time of year, as they try to build up fat reserves before hibernation. In the region, grizzly bears typically hibernate from November through April or May.