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 late on Thursday in Bella Coola, 435 miles (700km) north-west of Vancouver. The Nuxalk Nation said the aggressive bear remained on the loose 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.