At least five people were shot and killed on Sunday evening by a gunman who opened fire at a condo building in Vaughan, Ontario, the authorities said.
Scores of ambulances and police officers responded to the scene in Vaughan, a city about 20 miles north of Toronto.
Maniva Armstrong, a spokeswoman with the York Regional Police in Ontario, said in a brief interview on Sunday night that officers were still trying to determine how many people had been killed and injured in the shooting.
The gunman, whose name was not released, was fatally shot by police officers, Ms. Armstrong said. The authorities were not searching for other suspects, she added.
Investigators were looking into possible motives, she said. It was not immediately known whether the gunman had any connection to the victims, who were not identified.
Ms. Armstrong said that there could be more victims in the building.
“The officers are still at that building, clearing it,” she said.
This is a developing story.