Officials said the suspect, identified as 51-year-old Gabriel Wortman, also died in the weekend attack. Authorities did not provide a motive for the killings.

Royal Canadian Mounted Police Chief Superintendent Chris Leather told a news conference on Monday that police expect to find more victims once they are able to comb through all the crime scenes, some of which were houses set ablaze as victims were inside, adhering to government calls to stay at home because of the coronavirus pandemic.

Leather said police teams were spread out at 16 locations across central and northern Nova Scotia. He said some of the victims knew Wortman, and some didn't.

"We're relatively confident we've identified all the crime scenes," Leather said. "We have had five structure fires, most of those being residences, and we believe there may be victims still within the remains of those homes which burnt to the ground."

The dead included Constable Heidi Stevenson .

Another police officer was wounded by gunfire and was recovering at home, Leather said.

"The 18 innocent lives lost will be remembered throughout Canada's history," Public Safety Minister Bill Blair said .

Canadian Prime Minister Justin Trudeau noted how close-knit the small province of Nova Scotia is.

"The vast majority of Nova Scotians will have a direct link with one or more of the victims. The entire province and country is grieving right now as we come to grips with something that is unimaginable," Trudeau told a news conference.

"The pandemic will prevent us from mourning together in person, but a vigil will be held virtually to celebrate the lives of the victims," Trudeau added, saying it would take place Friday night through a Facebook group.

Trudeau asked the media to avoid mentioning the name of the assailant or showing his picture.

"Do not give this person the gift of infamy," he said.

The 12-hour rampage began late Saturday in the rural town of Portapique, about 100km north of Halifax, where police warned residents to lock their doors and stay in their basements as the attack unfolded.

The town, like all of Canada, had been adhering to government advice to remain at home because of the pandemic and most of the victims were inside when the attack began.

Several bodies were later found inside and outside one house on Portapique Beach Road, the street where the suspect lived, authorities said.

Bodies were also found at other locations within about a 50km area from the neighbourhood where the shootings began, and authorities believe the shooter may have targeted his first victims but then began attacking randomly.

Authorities said the gunman wore a police uniform and made his car look like a Royal Canadian Mounted Police cruiser.

They believe he acted alone.

Australian Associated Press