The suspect in Toronto tragedy where nine people were killed, was captured on video yelling at a police officer: "I have a gun in my pocket. Shoot me in the head".
The driver of a white rental van ploughed into pedestrians - including a woman pushing a stroller - in Toronto, before apparently confronting police.
Footage posted on social media from cellphones showed armed police telling the suspect to get out of vehicle.
He is heard yelling: "I have a gun in my pocket."
When the police repeat their command to step out of the van, he tells the officers: "Kill me!"
He adds: "Shoot me in the head."
A brief clip shows a police officer walking directly towards a suspect.
An officer says "No, get down!" and "I don't care! Get down!"
Authorities say the white van hit the crowd of pedestrians at the busy Yonge St and Finch Ave in north Toronto about 1.30pm local time (5.30am, NZT).
Police said nine people were killed and 16 injured. Toronto Police Deputy Chief Peter Yuen said: "Right right now we have nine people that are dead, 16 that are injured."
CBS identified the driver as 25-year-old Alek Minassian.
US law enforcement sources told CBS News that it appeared to be a deliberate act.
Reuters, citing a US security source, reported that terrorism is the leading theory about motive.
Former New York Police Commissioner Bill Bratton told MSNBC his sources in Canada said the van driver was known to police and considered it a terrorist attack.
But Canada's minister of public safety Ralph Goodale said it was too soon to say whether it was terrorism. He told reporters that police were still investigating and that Canada had not changed its terrorism alert level. He had no information suggesting a need to do so, he added.
The vehicle immediately fled but was found several blocks away, and the driver was taken into custody, police said. Fox reported witnesses as saying the driver was waving a weapon-like object at police.
Sky News reported that Toronto's Sunnybrook Hospital said seven patients from the van crash had been taken to the hospital and its emergency department was on lockdown as an "added precaution".
"We looked up and down the street and saw three or four victims on the ground, with pedestrians helping them," witness Saman Tabasinejad told the Toronto Sun. "I feel terrified, I grew up just around here."
Connie Lam lives nearby and told the Toronto Star she saw two more bodies at Mel Lastman Square and another across the street. Lam said the driver must have known to mount the southbound footpath because the northbound side had more concrete tree holders.
Witness Phil Zullo told Canadian Press he saw police arresting a man who had been driving a Ryder rental truck and saw people "strewn all over the road".
"It must have seen about five, six people being resuscitated by bystanders and by ambulance drivers," Zullo said. "It was awful. Brutal."
Taxi driver Agyeman-Badu told the Toronto Sun he had just dropped off a fare when he noticed a van driving on the footpath.
"It ran over a fire hydrant and just kept coming. I thought maybe the brakes weren't working because he kept coming," he said.
"There was an elderly lady at a bus shelter. She saw him and tried to step aside but she wasn't so lucky. He pinned her into the shelter and all the glass broke and fell on her.
"She was all cut up and unconscious when I went to help her. The van just kept going."
A driver described the horror: "He smashed into someone over there. Then I saw him go straight ahead. He's going 70-80 clicks. He's hitting people one by one. It's a nightmare, man.
"It's really bad, I can't believe it's happening. He hit every single person on the sidewalk. All I see is people crumbling one by one."
One witness said: "Everybody on the streets getting hit one by one, post office box getting crumpled up on people. One person got dragged, their blood is all over Yonge and Empress [Ave]."
A man who gave his name as Ali told CNN the driver appeared to be 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.
Bystander Essy Taeb told Toronto's CP24 television the scene was chaotic.
"Everyone was running all over the place," Taeb said.
A Reuters witness said at least two bodies were at the site.
Witness Carol Roberts told CTV News she saw "a lot of people lying lifeless on the ground".
Cabinet ministers from the G7 countries are gathering in Toronto to discuss a range of international issues in the run-up to the G7 meeting near Quebec City in June.
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 the tragedy happened.
"Our thoughts are with all those affected by the terrible incident at Yonge and Finch in Toronto. Thank you to the first responders working at the scene – we're monitoring the situation closely."
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 centre meridian dotted with planter boxes and sculptures.
Many people were out on the streets enjoying one of the first sunny days of spring in Toronto. 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 metres from emergency workers transferring people onto stretchers.
The United States and Europe have experienced a string of deadly attacks in which vehicles were used to mow down pedestrians, including an October 31 attack in New York that killed eight.
- With AP, AAP