After responding to an active shooting call about 7:20 pm at the residential building in Vaughan, just north of Toronto, police found a "horrendous scene where numerous victims were deceased," York Regional Police Chief Jim MacSween said during a news conference.

A male gunman, 73, was shot by an officer during a confrontation and died, the chief said.

Constable Laura Nicolle told CNN the incident was the "most terrible call I've seen in my entire career."

Police have not released the shooter's name and will not publicly name the victims until their families have been notified, the authorities said. Nicolle said the victims appeared to have been from more than one condominium unit.

Residents were evacuated while emergency response personnel worked to clear the building and ensure there were no more victims. The residents waited as police cleared the building floor-by-floor, eventually returning to their homes after midnight.

A motive in the shooting rampage has not been released and police did not share what led up to the killings. Authorities believe there is no longer any threat to the community.

"We offer our sincere condolences to the victims and their families," MacSween said.

The York Regional Police's homicide unit will continue investigating the shooting, MacSween said.

Ontario's Special Investigations Unit, which is called in when officers discharge their firearm at a person, said in a release it is investigating.

Canada: More gun restrictions than US

Sunday's killings come in the wake of fresh moves by Canada's government to tighten gun control laws in the country, which has more gun regulation and far less gun violence than the US.

Citizens may own firearms with a license; some must be registered.

This year, the government tightened restrictions further.

"As we see gun violence continue to rise ... we have an obligation to take action," Trudeau added. "Today our national handgun freeze is coming into force."