Police in Canada say two adults and four young children, the youngest of whom was less than three months old, are dead in a mass killing in what Ottawa’s mayor described as “one of the most shocking incidents of violence” in the city’s history.

A 19-year-old male is in custody and has been charged with with six counts of first-degree murder and one count of attempted murder.

Police were called to a house in the community of Barrhaven shortly before 11pm on Wednesday, where officers found what the Ottawa police chief, Eric Stubbs, called “a horrific scene”.

The victims were a “newcomer family” from Sri Lanka, said Stubbs, who named the victims as Darshani Bandaranayake Gama Walwwe Darshani Dilanthika Ekanayake, 35, and her four children: Inuka, seven; Ashwini, four; Rinyana, two; and two-month-old Kelly.

A 40-year-old man, Amarakoonmubiayansela Ge Gamini Amarakoon, who had recently come to Canada and was living in the house, was also found dead at the home.

“This was a senseless act of violence perpetrated on purely innocent people,” Stubbs told reporters at a news conference on Thursday afternoon.

The father, who police say was shouting for help in the street when officers arrived, remains in the hospital with serious injuries.

Stubbs says police are still trying to determine the relationship between the suspect, Febrio De-Zoysa, and the victims. De-Zoysa, who is also from Sri Lanka and was in Canada studying, is believed to have been living at the house as well.

Police initially called the event a “mass shooting” but later said an “edged weapon” was used in the killings.

Sri Lankan officials are in touch with their family members in Colombo.

“I was devastated to learn of the multiple homicide in Barrhaven, one of the most shocking incidents of violence in our city’s history,” Ottawa’s mayor, Mark Sutcliffe, said in a post on X.

Barrhaven East councillor Wilson Lo said he was “saddened to learn of the tragic loss of six Barrhaven neighbours last night”.

Ontario’s premier, Doug Ford, called the news of the mass killings in Ottawa “heartbreaking”, adding on social media that his “thoughts are with the family and friends of the six victims and the entire Ottawa community who is reeling from this terrible tragedy”.