They were talking tough in Canada yesterday.

Prime Minister, Stephen Harper insisted his nation would not be "intimidated" by the recent terrorist attacks in the country.

They served only to "strengthen our resolve and redouble our efforts... to take all necessary steps to identify and counter threats and keep Canada safe," said Mr Harper.

This is fighting talk that chimes with Ottawa's recent decision to join the US-led campaign of air strikes against Islamic State (IS) militants in Iraq.

While there remains no official confirmation this week's attacks in Canada are directly linked to IS or the new military campaign against them, few doubt such a connection exists.

Only last month, a video released by the IS's spokesman, Abu Muhammad Al-Adnani urged the group's supporters to kill Canadians and commit domestic attacks on Canadian territory.

Then last week US Homeland Security Secretary Jeh Johnson warned Canada could find itself subject to IS-inspired strikes and Canadian authorities raised the terrorism threat level from low to medium, citing online chatter from radical groups about targeting Canada.

It would be all too easy to think of sleepy Canada as a place far removed from the crosshairs of Islamic extremist terror attacks. But nothing could be further from the truth. Just like their counterparts in America, UK and other European countries, Canadian citizens are already deeply embroiled in the Middle East maelstrom IS has created.

"I was like any other regular Canadian. I watched hockey, I went to the cottage in the summertime, I loved to fish, I wanted to go hunting … I was a regular person," said Andre Poulin, aka Abu Muslim, in the last video he recorded before his death in August last year.

As one of the first known Canadians fighting for IS in Syria, Poulin was barely 20 when, in his home town of Timmins, Ontario, he embarked on the path toward a strict interpretation of Islam that led ultimately to his death as a jihadist fighter during an attack on a Syrian government controlled airport in the north of the country.

While Poulin never returned home to his native Canada, others who have fought for IS and a myriad of Islamic extremist groups will undoubtedly make it back to their home soil, bringing with them serious threats.

According to Sir Bernard Hogan-Howe, the head of the Metropolitan Police, an estimated average of five young Britons are travelling to Syria each week to fight for IS. It is not a question of if, but when, such individuals operating as lone wolf activists of as part of a cell succeed in carrying out attacks.

Those trained and with battlefield experience in places like Syria and Iraq clearly pose a major threat, being more capable of executing so-called terrorist "spectaculars" or substantial attacks.

Naturally, this is cause for serious concern, though on the positive side many of these battle-hardened jihadist veterans are more likely to register on the radar of security and intelligence agency monitoring.

Not so with what are dubbed in security circles as "grassroots jihadists", like Michael Zehaf-Bibeau, the Muslim convert who carried out Wednesday's attack in Ottawa.

Eager to fight and inflict damage, these grassroots jihadists, by and large, fortunately lack the terrorist tradecraft required to conduct a more sophisticated attack. The downside is they are often much more difficult to identify and monitor, being deeply embedded within the community at large.

Those among their ranks who decide to conduct simple attacks, such as the Boston Marathon bombers, generally succeed, having slipped the notice and surveillance implemented against terrorists with track records.

The process of getting personnel and weapons into places to carry out a substantial attack poses a range of covert operational and logistical problems. By contrast, tapping into the mindset of the grassroots jihadist via the internet is comparatively easy.

In Canada last Monday this was highlighted by the first of the week's two terrorist strikes when Martin Rouleau, a 25-year-old "radicalised" Quebec man and grassroots jihadist, ran over two Canadian soldiers in Saint-Jean-sur-Richeliu with his car.

Security sources say a review of Rouleau's social media accounts shows he had a distinct attraction toward jihadism, including Twitter accounts, many of which are associated with IS.

According to the independent US-based intelligence think-thank Stratfor, Rouleau's vehicle attack is very similar to a tactic al-Qaeda in the Arabian Peninsula (AQAP) advocated in the second edition of its online magazine Inspire.

In that article grassroots jihadists were encouraged to run over victims using large heavy vehicles, a directive repeated in a statement released on September 21 by IS spokesman Abu Mohammed al-Adnani. The statement makes for chilling reading and talks of killing with whatever means lie at the attackers' disposal: "You must strike the soldiers, patrons, and troops of the tawaghit (those who worship anything except Allah) ... If you are not able to find an IED (Improvised Explosive Device) or a bullet, then single out the disbelieving American, Frenchman, or any of their allies. Smash his head with a rock, or slaughter him with a knife, or run him over with your car, or throw him down from a high place, or choke him, or poison him."

For those jihadis, battle-hardened veterans and grassroots alike, such instructions will doubtless continue to act as tactical manuals for the violence they inflict.

Some within the intelligence community, however, say such instructions and methods of delivering terror indicate a sign of weakness and dwindling of strength in the global jihadist movement.

In the post-9/11 world of counterterrorism operations, drone strikes, vastly improved intelligence and data bases, critics argue such statements reveal the ever-increasing constraints jihadist groups face in trying to impose their terrorist capability in the current global security climate.

Such an assessment will come as little consolation to the families and loved ones of those who remain victims of IS and other extremists.

For all the talk of having al-Qaeda and its ilk on the run, the threat of terrorism, as IS has shown, is likely to be a persistent one that will require a long-term strategy to identify and deter wherever it emanates from.

The attacks in Canada this week may well have been small scale, but they still have the power to shock the world, to bring attention and attract more support for the jihadist cause.