Toronto Deputy Chief Peter Yuen provided the casualty toll at a news conference.
The incident occurred just before 1:30 p.m. (1730 GMT) as large crowds of office workers were on lunch breaks. At least one witness described the driver as appearing to deliberately target victims on his roughly mile-long (1.6 km-long) rampage. The driver was in custody, police said.
Police in Canada's largest city initially said eight to 10 people had been injured but later said it was unclear exactly how many had been hurt or the extent of their injuries.
A Reuters witness said there were at least two bodies at the site of the incident. At least seven people were brought to nearby Sunnybrook Health Services Centre's trauma center, the hospital said on Twitter.
It was not immediately clear if the incident was a deliberate act by the driver or a traffic mishap in a mixed commercial and residential area.
The crash occurred at the corner of Yonge Street and Finch Avenue in the north end of the city, where a van drove onto the sidewalk and hit several people, said Toronto Police spokeswoman Meaghan Gray.
A man who gave his name as Ali told CNN he saw the van and that the driver appeared to have been targeting people.
"This person was intentionally doing this, he was killing everybody," the man said. "He kept going, he kept going. People were getting hit, one after another."
He said a number of the victims were older people and at one point he saw a stroller fly into the air.
At least one person was struck outside on the sidewalk outside an Anglican church, about 1.5 kilometers (0.9 miles) north of where the van came to rest in front of a currency exchange in a condominium tower.
Buildings and workplaces in the area where the van struck pedestrians in Toronto were locked down, and a nearby subway station was closed and service suspended.
Yonge Street is large, divided boulevard at the point where the incident occurred, its center meridian dotted with planter boxes and sculptures.
Some of the victims were struck in a public square popular with office workers on lunch breaks. Aerial photos of the scene posted on social media showed a food truck parked just a few feet away from where emergency workers busily transferred people onto stretchers.
The incident happened about 30 kms (18 miles) from downtown, where the Group of Seven foreign ministers of industrialized nations, including Canada, the United States, Britain, France, Germany, Italy, and Japan were meeting on Monday. There was no noticeable change in security around the Intercontinental Hotel where the ministers gathered.
Canadian Prime Minister Justin Trudeau said officials were investigating.
"We're still gathering information and as soon as we can, we'll share more information with Canadians," Trudeau told reporters about an hour after news of the incident broke.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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