Ten people are dead and 15 others are injured after a van driver plowed into a number of pedestrians Monday in the Yonge Street and Finch Avenue area of North York in Toronto.

One suspect is in custody.

CBC News has confirmed that Alek Minassian, a 25-year-old Richmond Hill, Ont., man, is the alleged driver in the attack. His LinkedIn profile identifies him as a student at Seneca College.

Government officials briefed on the investigation so far say the suspect is not associated with any organized terrorist group and he does not represent a larger threat to national security.

Police gather after a van driver ran down a number of pedestrians on Monday in north Toronto. (Aaron Vincent Elkaim/Canadian Press)

The officials spoke on condition of anonymity because they were not authorized to speak publicly about the investigation.

All available resources mobilized: police

Toronto police Deputy Chief Peter Yuen told reporters police have mobilized all available resources and that officers expect to be at the scene for a number of days to come.

Alek Minassian, 25, is the suspect in the Toronto van attack that killed 10 people and injured 15 others. (Alek Minassian/LinkedIn)

"This is going to be a long investigation," Yuen said. There were numerous witnesses and surveillance cameras in the area, he said.

Police were called to the Yonge and Finch area for a report of a crash around 1:30 p.m. after a van mounted the curb and hit pedestrians on the sidewalk before being stopped by police.

"There were a lot of pedestrians out enjoying, a lot of witnesses out enjoying the sunny afternoon," Yuen said. Police are establishing two hotlines — one for victims and their families, and the other for witnesses to call in information related

to the incident.

Terror-threat level remains unchanged

A witness said separately that he had seen at least four bodies lying covered on the ground and that the people hit included a man who was crossing the street and others on the sidewalk.

Police inspect a Ryder van suspected of being involved in the collisions injuring numerous people at Yonge and Finch. (Warren Toda/EFE/EPA)

Amir Bahmeyeh, a student, was in the area at the time of the attack.

"I saw the crazy van, like a rental van, hitting the people … one after one," he said. "I'm sure it was like a terrorist attack because he drove really fast, like crazy.

"Kill me," the man can be heard yelling as Toronto police arrested him 1:13

"I almost had a heart attack. When I came here people told me it was a safe country and that's why I stayed here," said the student, who said he'd come from Iran.

"Now, I saw the accident, maybe I go back my country," he said.

In a tweet, Sunnybrook Hospital said 10 victims were transported to its trauma centre. Two of those are among the dead, while five are in critical condition, two are in serious condition and one is in fair condition. The hospital's emergency department has been locked down as a precaution, it said.

People react after a van struck multiple people in north Toronto. (Carlo Allegri/Reuters)

In a statement, Ryder, the company from which the van was rented, said it was co-operating fully with authorities.

Public Safety Minister Ralph Goodale said he cannot confirm whether the incident is being treated as a terror incident, but he referred to it as an "attack".

Witness talks about van striking pedestrians 0:32

"There is no information available to me at the present time that would indicate a change in the risk level," Goodale told reporters in Toronto, where he is attending the G7 foreign and security ministers meeting.

Canada's threat level remains unchanged for the time being, he said.

'United in grief'

Meanwhile, Mayor John Tory said his office was being updated by Toronto Fire Service, Toronto Paramedic Services, the TTC and the acting city manager.

"My heart goes out to the families and loved ones of the nine people killed and 16 injured in today's cowardly and incomprehensible attack in Toronto," he said.

The city is "united in grief," the mayor said.

Prime Minister Justin Trudeau expressed condolences as he was heading into question period in Ottawa. He said he was just learning of the incident. "Our hearts go out to everyone affected."

Trudeau said he would have more to say in the coming hours.

Onlookers gather at Yonge and Finch after the van hit multiple pedestrians. (Jon Tam)

Meanwhile, the head of the Toronto Police Association said it is bringing in counsellors for officers who responded to the attack.

"Nobody's seen anything like this. I've been in policing for 30 years, we've never seen this and again, unfortunately, this is the new world order and we're very concerned about it," Mike McCormack said.

An unidentified woman, who police say witnessed a van striking multiple people at Yonge Street and Finch Avenue in Toronto, reacts to the horror Monday afternoon. Ten people were killed and 15 injured, police say. (Carlo Allegri/Reuters)