Photo used for illustrative purpose.

Police quickly arrested a man and said the deaths did not appear to be linked to domestic or intimate partner violence. "The scene is obviously a horrific one," police chief Eric Stubbs told the Canadian Broadcasting Corporation, without providing details on how the victims died.

Canada's Prime Minister Justin Trudeau expressed his "shock and horror" at what he called a "terrible tragedy."

Speaking at a press conference, Trudeau said: "Obviously, our first reactions are all ones of shock and horror at this terrible violence... And we expect the police of jurisdiction to be doing the work and keeping us all informed of this terrible tragedy."

Ottawa mayor Mark Sutcliffe, in a social media post, said it was "one of the most shocking incidents of violence in our city's history."

"I was devastated to learn of the multiple homicides in Barrhaven, one of the most shocking incidents of violence in our city's history. We are proud to live in a safe community but this news is distressing to all Ottawa residents," Mark Sutcliffe tweeted.

Ottawa, which has a population of one million, saw 14 murders in 2023 and 15 in 2022.

The victims were found inside a house in the southwestern suburb of Barrhaven and have not been identified. Police arrived on the scene following emergency calls shortly before 11pm on Wednesday, they said in a statement.

Mass killings in Canada are infrequent. In December 2022, a man shot five people in a Toronto suburb before being gunned down by police.

In September that year, a man stabbed and killed 11 people in the western province of Saskatchewan. He died of a cocaine overdose shortly after being arrested by police.

Agencies