A grizzly bear has attacked a group of schoolchildren and teachers on a walking trail in British Columbia, Canada, injuring 11 people, two of them critically.

The attack happened on Thursday afternoon in Bella Coola, 700km northwest of Vancouver.

The Nuxalk Nation, the local administration, said the “aggressive bear” remained on the loose on Thursday evening and police and conservation officers were on the scene.

“Officers are armed. Remain indoors and off the highway,” the First Nation said in a social media post.

Two people were critically injured and two had serious injuries, Emergency Health Services spokesman Brian Twaites said.

The others were treated at the scene.

Parent Veronica Schooner said a lot of people tried to halt the attack but one male teacher “got the whole brunt of it” and was among the people taken by helicopter from the scene.

Schooner’s 10-year-old son Alvarez was in the class of fourth- and fifth-graders that was attacked and was so close to the animal “he even felt its fur,” she said.

“He said that bear ran so close to him but it was going after somebody else,” Schooner said.

She added that some children were hit with bear spray as the teachers fought off the bear and Alvarez was limping and his shoes muddy from running for safety.

Her son’s thoughts, however, were with his classmates.

“He keeps crying for his friends, and oh my goodness, right away he started praying for his friends,” she added.

Acwsalcta School, an independent school run by Nuxalk First Nation in Bella Coola, said in a Facebook post that the school will be closed on Friday and counselling made available.

“It’s hard to know what to say during this very difficult time. We are so grateful for our team and our students,” the post said.

—AAP