At least nine people were killed in a mass shooting at a high school and a nearby residence in Tumbler Ridge, British Columbia, marking Canada’s deadliest school shooting in decades, authorities said Tuesday.

Police responding to reports of an active shooter at Tumbler Ridge Secondary School around 1:20 p.m. found six people dead and dozens injured. One victim later died en route to hospital.

Two additional fatalities were discovered at a residence believed to be linked to the incident.

The suspected gunwoman was found dead inside the school from what police described as a self-inflicted injury. Authorities have not released her identity or motive.

Two victims were airlifted with life-threatening injuries, while about 25 others with non-life-threatening wounds were treated locally.

The school, which serves around 175 students from Grades 7 to 12, and nearby campuses will remain closed for the rest of the week.

Royal Canadian Mounted Police Superintendent Ken Floyd said investigators are working to determine what led to the attack and whether victims had any connection to the suspect. Officials confirmed there is no ongoing threat to the public.

David Eby called the incident a “devastating and unimaginable tragedy,” while federal and provincial leaders extended condolences to the tight-knit mountain community of roughly 2,400 residents.

Mass shootings remain rare in Canada, where firearm regulations are significantly stricter than in the United States.