The Canada Border Services Agency issued an “armed and dangerous” alert to its officers stationed along the Canada-U.S. border, warning them of the man suspected of having shot at least 18 people in southern Maine.

The shooting incident was reported on Wednesday night in Lewiston, about 260 kilometers southwest of the New Brunswick border.

A police bulletin identified the suspect as 40-year-old Robert Card, a firearms instructor believed to be in the U.S. Army Reserve and assigned to a training facility in Saco, Maine.

As the intense search for Card continues today, residents of southern Maine have been asked to lock their doors and stay indoors.

The Canada Border Services Agency says it is working with Canadian and U.S. law enforcement partners, including U.S. Customs and Border Protection and the Royal Canadian Mounted Police, “to protect Canada’s borders from any threats or attempts at illegal entry.”

The Canada Border Services Agency stated that a “firearms and dangerous person alert” was sent to all its officers through an internal system, and the agency added that all entry points along the Canada-U.S. border remain open.