TWO young people have died and up to 19 people, including an infant, have been wounded in a shooting at a crowded outdoor barbecue party in Canada's biggest city, Toronto.
Bullets from more than one gun were sprayed into the crowd of more than 200 people.
"It is the most serious crime of its kind that has ever taken place in the city of Toronto," said Police Chief Bill Blair.
Police made multiple appeals for witnesses to contact them as they began to pull together descriptions for what appeared to be multiple shooters.
Police said they had one "person of interest" in custody and were looking for other suspects.
The incident took place before 11pm local time on Danzig Avenue, near Morningside Avenue and Lawrence Avenue East in the city's east side.
"An altercation broke out among some individuals and there was an exchange of gunfire. During that gunfire a number of innocent bystanders were struck," said Blair.
"It's a very shocking event, a lot of people were injured tonight."
The two killed in the shooting were a teenage girl and a man in his 20s, officials said.
Blair did not provide the age of the child who was injured but says the injuries are "not life-threatening and the child will be fine".
Those hurt in the incident suffered a mix of gunshot wounds and injuries from the mass panic that ensued.