Pandemonium broke out in Nathan Phillips Square in Toronto after some gunshots were heard.
This came near the end of a massive celebration in response to the Raptors winning their first NBA championship.
According to the Toronto Police Service, two victims have been located and two people are in custody.
None of the injuries are considered life-threatening.
Police have also recovered two firearms.
The shootings occurred after millions had showed up at a parade honouring the team.
Some in the crowd panicked after realizing what had occurred. (Video is available on the Toronto-based CityNews website.)
CBC reporter Meagan Fitzpatrick tweeted video of the crowd dispersing.
Toronto Police have also reported that three people were stabbed at the entrance to Eaton Centre Plaza after a fight broke out.
The Toronto Police Service issued a news release at 4 p.m. Pacific daylight time saying that there are four victims with injuries linked to the shooting. Three people have been arrested.