Ten people, including a suspected shooter, were found dead following a mass shooting in a town in northeastern British Columbia on Tuesday, Canadian police said.

Six people were found dead inside a high school in Tumbler Ridge, two more people were found dead at a residence believed to be connected to the incident, and another person died on the way to hospital, the Royal Canadian Mounted Police said.

The RCMP also revealed that more than 25 people were injured, including two with life-threatening injuries from the shooting.

The town of Tumbler Ridge, which has a population of about 2,400 people, is located more than 1,000 kilometers north of Vancouver, near the border with Alberta.

"As part of the initial response to the active shooting, police entered the school to locate the threat. During the search, officers located multiple victims. An individual believed to be the shooter was also found deceased with what appears to be a self-inflicted injury," RCMP said in a statement.

The shooter may have been a woman, as an official active shooter alert put out in British Columbia described the suspect as a brown-haired female in a dress.

The Peace River South School District said earlier on Tuesday that there was a "lockdown and secure and hold" at both the secondary school and the Tumbler Ridge Elementary School.

Larry Neufeld, a member of the legislature for Peace River South, told reporters that an "excess" of resources, including RCMP and ambulance support, has been sent to the community.

Tumbler Ridge Secondary School has 175 students enrolled in Grades 7 to 12, according to the provincial government website.

Agencies contributed to this story.