A Toronto police officer was shot dead early Thursday during a raid on an apartment linked to the March attack on the U.S. consulate, the city's police chief said.

Toronto police chief Myron Demkiw said 43-year-old constable Marc Pinizzotto was shot while conducting an early morning search warrant in the northwest of the city and later died at a hospital.

The warrant "concerned a number of shootings, including the shooting at the United States consulate," Demkiw said.

A 19-year-old suspect remained at-large, Demkiw said.

Toronto police said in March that two men fired multiple rounds at the empty US diplomatic building before sunrise.

No one was hurt in the incident that the US ambassador to Canada, Pete Hoekstra, called "deeply troubling."

Canada's federal police have said the investigation into the consulate shooting would determine weather it amounted to a "terrorist" event.