A man plowed a white rental van into a crowd of pedestrians in the centre of Canada's biggest city Toronto yesterday, police said, with several people feared dead.

Police said up to 10 people were struck, adding they could not confirm any deaths, but local media reported at least four fatalities in the incident.

Television images showed the man and a police officer facing off, their guns drawn. The suspect eventually surrendered his weapon and was taken into custody.

Vehicle attacks have been carried out to deadly effect by extremists in a number of capitals and major cities, including London, Paris, New York and Nice, but the motive for Monday's incident was not yet clear.

"Update: unknown of extent of injuries, possible 8-10 pedestrians struck," Toronto police wrote on Twitter.

Police then said it was "too early to confirm the number of pedestrians struck or their injuries."

At least one body was seen covered at the scene. At least seven patients were being treated at the Sunnybrook Health Sciences Centre, the facility said on Twitter.

Officers were called to the scene -- on Yonge Street at the corner with Finch Avenue -- at 1:27 pm (1727 GMT).