The Royal Canadian Mounted Police (RCMP) identified the shooter in the rural community of Portapique as 51-year-old Gabriel Wortman and asked residents not to approach him.
Wortman is currently in a vehicle that resembles a RCMP vehicle and wearing a RCMP uniform, the police said in a series of tweets.
Mass shootings are rare in Canada where gun laws are stricter compared to those in the United States.