One man was killed and six other people were wounded by gunfire, two critically, in a shooting at Toronto's main downtown mall.
One of the victims in critical condition is a 13-year-old boy, a police spokesman said.
Seven people in total were shot or grazed, while a pregnant woman was knocked down in the melee that followed and went into labour.
Police said the shooter was still at large.
"It's terrible when you hear something like this. My heart goes out to the families that have been affected by this terrible crime. We have to apprehend this shooter," Toronto Mayor Rob Ford, who was visibly distraught, told reporters at the scene.
The shooting happened shortly after 6pm local time in a food court at the Eaton Centre, one of the city's top tourist destinations.
The building was evacuated and quickly surrounded by dozens of police cars, emergency vehicles and forensic vans.
Police said the man killed was 25 years old, while the other victim in critical condition was a 20-year-old man.
Toronto police chief Bill Blair told reporters the injuries suffered by the fatal gunshot victim suggested he had been targeted.
Two women and another man suffered serious gunshot wounds, while another woman was grazed by a bullet, police said.
The incident revived memories of another shooting that happened just north of the Eaton Centre on 26 December 2005, in which a 15-year-old girl was killed and several other people were wounded. That shooting was believed to be gang-related.
Canada has stringent controls on handguns and a lower rate of gun-related violence than the United States. But mass shootings are not unknown.
In 1989, a lone gunman targeting women killed 14 people at a Montreal university, an event that became known as the Montreal Massacre.
