Gunshots were fired at the championship parade of the Raptors in Toronto, Canada. Four people sustained non-life-threatening gunshot wounds, Toronto Police Chief Mark Saunders said.
Three arrests were made, according to Saunders, who added that the investigation was ongoing.
The shooting occurred in the area of Nathan Phillip's Square, Bay Street and Albert Street.
Addition people sustained minor injuries attempting to flee the scene after the shots were heard.
Several Twitter users took to social media to report about the shots. One witness said four shots were heard and that they triggered a stampede.
In the immediate aftermath of the shooting, Jewish rapper Drake took the stage and invited the reported 1.5 million people attending the event to hug each other and spread love, TMZ reported.
According to TMZ, the parade ended with no further problem.
Mayor John Tory said in a statement, "It is disappointing and I'm sure a source of anger for more than just me that anyone would carry a gun and discharge it at what was otherwise a joyous celebration.
"I hope those responsible will be held to account to the full extent that the law permits. I want to commend and thank the millions of other people who happily and peacefully celebrated our beloved Toronto Raptors."
Tory and Canadian Prime Minister Justin Trudeau were with the Raptors players on stage at the rally when the shots occurred. The festivities were briefly paused before resuming.
Trudeau's spokeswoman declined comment on the fact that the nation's leader was nearby to a shooting.
The Raptors were celebrating their first NBA title, and the first by a Canadian team, four days after Toronto completed a six-game win in the NBA Finals against the two-time defending champion Golden State Warriors.