The pair of attacks in Edmonton that left a police officer and four pedestrians with undisclosed injuries on Saturday night opens a new chapter for terror in Canada, according to one expert.

The incident adds the first Canadian city to a growing list of places where vehicles have been the weapon of choice to inflict indiscriminate violence against crowds of innocent civilians.

Amarnath Amarasingam, an expert on extremism at the University of Waterloo, points out that ISIS has been urging followers to attack wherever in the world they may be for a long time.

"Any Western city will do, whether in Europe or North America," he told The Canadian Press. "For them, it's about sowing fear, turning communities against one another, and creating the impression that they are everywhere."

“It is really the first time the ISIS playbook of attack, ramming people with cars and that sort of thing, is hitting the public in Canada,” CTV Public Safety Analyst Chris Lewis added. “It is a bit of a wake-up call I suppose.”

A 30-year-old male suspect is being questioned by police after a white Chevy Malibu plowed into a crowd control barricade outside Commonwealth Stadium, tossing an officer about five metres into the air before slamming into a parked cruiser. Video shows the driver exit the car and appear to stab the injured officer on the ground in plain view of bystanders.

Hours later, a U-Haul cube van approached the stadium where members of the military were being honoured at a CFL football game. The driver sped off when asked for identification, swerving towards pedestrians during a police pursuit.

"I'm not sure how you're going to stop an attack of this nature," Phil Gurski, a threat consultant in Ottawa and former analyst with the Canadian Security Intelligence Service, told the Canadian Press. "It's impossible to stop unless the person's already on your radar."

Edmonton Police Chief Rod Knecht said the suspect was known to authorities, but there was no warning of the attack.

Lewis said targeting law enforcement and military personnel is a common theme for ISIS. An ISIS flag was found in the front seat of the car, but it is not known to what extent, if any, the terror group was involved.

Lewis describes the incident as a “classic ISIS method of operation,” though he doubts the suspect has tangible ties to the group.

“It was probably a lone wolf, although I hate that term. Somebody who has been radicalized in some way and brought into this extremist mindset, as opposed to someone who was directed by ISIS,” he told CTV News Channel.

Edmonton Mayor Don Iveson said the working theory among investigators points to a “lone wolf,” in a media address on Sunday.

Lewis also notes the perpetrator of Saturday night’s violence appears to have lacked coordination and planning.

“It was a simple thing. He had a knife, no guns, no bombs. (He) drove his own vehicle, reportedly, into the police and then fled on foot. It’s not like he had a getaway car sitting there,” he said.

Stephanie Carvin, a terrorism expert at Carleton University, also thought the attack looked unsophisticated.

"It seems to have been carried out very badly (thankfully) so probably not a mastermind here, folks," she said on Twitter. "But attacks against crowds and sports fans has been a HUGE fear in Canada over the last 18 months. This will not help that."

According to a briefing note prepared last November, Canada's spy agency views terrorist acts at home as a "constant" threat.

"The principal terrorist threat to Canada remains that posed by violent extremists who are inspired to carry out an attack in Canada," reads the document obtained by The Canadian Press under Access to Information legislation.

"Terrorist activity can be sudden or spontaneous, or in some cases, take months or years in planning and logistics."

The document also said CSIS is studying "behavioural indicators" that would indicate if an individual is moving from holding extremist ideas to taking action.

With files from The Canadian Press