Ten people are dead and 15 others remain in Toronto-area hospitals fighting for their lives after a van mounted a curb in North York, striking “numerous pedestrians” in its path.

Toronto police say were first alerted to the incident at around 1:27 p.m. after receiving a number of calls from citizens reporting a traumatic hit-and-run on Yonge Street between Finch Avenue and Sheppard Avenue.

“The driver is in custody and he’s being investigated (in connection) to the events that took place this afternoon,” Dept. Police Chief Peter Yuen said at a news conference shortly before 5 p.m. on Monday.

A suspect identified as 25-year-old Alek Minassian, of Richmond Hill, has been arrested in connection with this case, police said. Sources told CTV News Minassian is not known to police.

“This is going to be a long investigation," Yuen said. "We have multiple witnesses. We have a lot of surveillance cameras and namely, at 1:30 this afternoon there were a lot of pedestrians out, a lot of witnesses enjoying the sunny afternoon. We’re urging anyone that saw anything to please call Crime Stoppers or Toronto Police and let us know.”

Sunnybrook Hospital confirmed 10 people were admitted to the trauma centre for treatment following the incident.

The hospital says two people arrived without vital signs and were later pronounced dead. Five others remain in critical condition, one person is in serious condition and another is in fair condition. Dr. Dan Cass of Sunnybrook told reporters that all the victims received are adults.

He added that any family members seeking information on patients should call 416-480-4940.

A representative for North York General Hospital said it received four patients, one of which is in critical condition. The other three people are in “stable” condition, according to hospital.

Speaking at the same news conference, Toronto Mayor John Tory urged businesses in the vicinity of the scene to close for the day so that police could focus on their “very complicated investigation.”

Businesses on the east side of Yonge Street have been asked to let employees exit onto Doris Avenue and those on the west side have been asked to let employees exit onto to Beecroft Road.

The typically busy stretch of Yonge Street is expected to be closed or disrupted “for several days.”

“In other words, we’re trying to keep people off Yonge Street near the scene of this tragedy so that the police can continue with their investigation,” he said.

Tory said officials are in the process of establishing two hotlines – one for families of those concerned about their loved ones and another where citizens can report “any information whatsoever” about the incident.

“It is a time to be as calm as we can be in the city, to understand that our first responders are doing their jobs, especially the police,” he said. “I hope people won’t forget that spirit of unity and solidarity and that sense of calm we should have as people go about dealing with an awful tragedy.”

Suspect arrested, van seized

Police arrested one man and seized a white van during a dramatic takedown a short distance away from the initial scene.

Witnesses reported seeing a white van "crashing into everything" before being apprehended on a sidewalk on Poyntz Avenue, just south of Sheppard Avenue West.

A man was seen next to a white rental van, pointing what appeared to be a gun at police officers. Officers could be heard shouting, “get down!”

After a brief standoff, the suspect can be seen dropping whatever was in his hands as police quickly surround him and take him into custody.

Sources told former police homicide detective and CP24 crime specialist Steve Ryan that the suspect at one point was asking police to shoot him.

The front-end of the white van appeared damaged with the hood of the vehicle bent open.

In a news conference at 8 p.m., Toronto Police Services Chief Mark Saunders said a motive has not yet been determined.

He did say that based on witness accounts, the incident “looked deliberate.”

Anyone with any information regarding this investigation is asked to call officers at 416-808-8750 or submit footage to a web portal that has been set up by police.

“We’re making the appeal to anyone who saw anything or anyone who has any information with regards to this investigation to call,” Saunders said.

“This happened during a very busy time in the city of Toronto on one of the busiest streets in the country, there are a multitude of people that may have witnessed it and as a result are concerned or have issues regarding wellness.”

Saunders encouraged concerned Torontonians to contact victim’s services at 416- 808-7066.

Video from the CTV News Toronto helicopter showed paramedics treating several people near what appeared to be blood stains on the sidewalk.

“I turned my head and I saw the van hitting a man walking through the intersection,” one witness told CP24. “We stayed with the man to make sure he was okay… He was conscious… He hung in there. I hope he’s going to be alright.

The same witness said he saw some people “lying on the sidewalk in pools of blood.”

“I feel sick to my stomach,” he said. “What can I say… I’ve never seen anything like this before.”

Another witness, who identified himself only as Ali, described the scene as “a nightmare.”

“I thought he had a heart attack or something, so I was trying to chase it down in a way, to try and catch up and see what happened. All I saw is this guy – and he’s going 70, 80 clicks – he’s just hitting people one by one,” Ali said, his voice choked with emotion.

“I couldn’t believe what I saw… All these people on the streets getting hit one by one.”

Along with the closure along Yonge Street near Finch and Sheppard, the TTC has shut down subway service on Line 1 between Sheppard and Finch stations due to the investigation.

Cardinal Carter Academy for the Arts was also been placed under a hold and secure.

Additional safety measures, including road closures around Maple Leaf Square and the Air Canada Centre, were implemented for Monday night’s Toronto Maple Leafs playoff game.

“Our organization continuously works in close partnership with Toronto Police Service, and other security agencies, to ensure the safety of all fans attending games at Air Canada Centre, including playoff tailgate events at Maple Leaf Square,” a statement from the Toronto Maples Leafs and MLSE said.

Enhanced security was also implemented inside the arena during the game.

Tory confirmed the road and transit closures could continue for another day due to the police investigation. He encouraged pedestrians and drivers to stay away from the area.

“Tomorrow it will still be an active investigation scene,” he said.

Saunders said that there is still “tremendous amount of work going on” and it will take time to process the scene.

Terror threat level unchanged

Saunders said the Toronto police are working with their provincial and federal counterparts, but it is too early in the investigation to determine if the incident was an act of terrorism. He said he was keeping “all lanes open” until all evidence was collected.

Ralph Goodale, Canada’s minister of public safety, says there is “no information” presently available to prompt a change in the country’s terror threat level.

Canada's National Terrorism Threat Level has been listed as "Medium," which means that a violent act of terrorism could occur. It has been that way since October 2014.

“The appropriate authorities of the Government of Canada in collaboration with all of their relevant law enforcement partners are constantly assessing and reassessing the nature of risk in the country from whatever source it may come,” Goodale told reporters at an unrelated event on Monday. “If they conclude that a change is appropriate, that decision is made by the key senior officials within the Government of Canada. I think it’s important to state this – there is no information to me at the present time that would lead us to conclude that there should be a change in risk level.”

Goodale said police are working “as rapidly as possible” to identify “precisely what has taken place.”

RCMP has been made aware of the situation and is working in conjunction with security officials at both the municipal and federal levels, he said.

“The Toronto police service is the lead investigative agency in this matter and I understand that as soon as they are able to comment further with information or details, that they will be making the appropriate officers available but until they are able to do that, it is not possible at this stage for us to speculate on the situation,” he said.

Prime Minister Justin Trudeau also commented about situation shortly before a session in the House of Commons.

"Obviously we're just learning about the situation in Toronto. Our hearts go out to anyone affected," Trudeau said on Monday afternoon. "We're going to obviously have more to learn and more to say in the coming hours."

Premier Kathleen Wynne also weighed in on the incident and thanked first responders for “caring for victims and witnesses.”

“My thoughts are with everyone affected,” she wrote on Twitter. “We’re following the situation closely – working with our federal and municipal partners.”