Western powers must ramp up air strikes by 10 to 20 times to have any hope of disrupting the Islamic State group, which risks turning Europe into an urban guerrilla warzone, warned one of the world's leading counter-terrorism experts.

David Kilcullen, an Australian army veteran, became the senior counter-insurgency adviser to U.S. General David Petraeus during the Iraq War and is considered a key architect of the "Awakening" strategy that helped turn the conflict around.

Ten years after she took office, German Chancellor Angela Merkel stands alone as the leader of a European Union that is grappling with multiple crises, despite the fact she has been weakened domestically, analysts say.

Merkel's trailblazing decision to welcome refugees during the migration crisis came after she led the European Union's response to the Ukraine conflict and helped keep Greece in the eurozone.

The tide of global rage against the Islamic State group lends greater urgency to ending the jihadis' ability to operate at will from a base in war-torn Syria. That momentum could also force a reevaluation of what to do about President Bashar Assad and puts a renewed focus on the position of his key patrons, Russia and Iran.

The Syrian leader has lost much of the country to IS and other groups in the four-year war; half the population has been displaced, many areas have been leveled, and masses of refugees are flooding Europe. Along the way, Assad's brutal military response has made him persona non grata in most of the world.

Canada is going full-steam ahead with new leader Justin Trudeau's plan to take in more than 25,000 Syrian refugees by year's end, but the drive has split the nation as the Paris attacks raise security fears.

Dueling online petitions for and against fast-tracking refugee claims have gathered steam in Canada since the attacks claimed by the Islamic State group, with some 45,000 for and 70,000 against as of Tuesday.

The Islamic State jihadist group, which holds large areas in Iraq and Syria and has affiliates and operatives in other countries, claimed attacks in Paris that killed 129 people.

But how does IS function, and who calls the shots?

France's security services are once again facing a harsh spotlight after failing to prevent the brutal attacks in Paris carried out by the Islamic State group.

There is particular concern over the failure to intercept 28-year-old Frenchman Samy Amimour, one of the suicide bombers in the massacre at the Bataclan concert hall.

The deadly Paris attacks have reignited debate on encrypted communications by terror cells and whether law enforcement and intelligence services are "going dark" in the face of new technologies.

The exact means of communication in Friday's strikes were not immediately clear, but media reports have said the Islamic State organization has increasingly turned to encrypted communications and applications to avoid detection.

The Paris attacks and the discovery of a Syrian passport near one of the assailant's bodies have revived the European debate on whether to take a harder line on migrants.

With the continent facing its biggest migration crisis since World War II, EU states have bickered for months on how to stem the flow and share out the new arrivals.

Several foreigners have been identified among the victims of Friday's deadly terrorist attacks in Paris, which left at least 129 dead and more than 350 injured:

According to an AFP tally from various official sources around the world, at least 23 foreigners lost their lives in the attacks.

The suicide vests used by Friday's attackers in Paris -- a first in France -- were made by a highly skilled professional who could still be at large in Europe, intelligence and security experts say.

All seven of the militants wore identical explosive vests and did not hesitate to blow themselves up -- a worrying change of tactic for jihadists targeting France.