The Islamic State’s war on Europe seems to have entered a dangerous new phase, evolving from highly coordinated operations on the grand boulevards of Paris and Brussels to amateur assaults in the hinterlands that have suddenly turned anyone, anywhere into a target.

The rapid-fire nature of the attacks in Europe over the past two weeks is confounding European intelligence agencies, at times turning terror response into a ground war fought by already-stretched local police. Following the latest attack — the brutal slaying on Tuesday of a small town priest in France — the violence has felt almost like the start of the uprising that the Islamic State has been attempting to spark among its sympathizers in the West for years.

The attackers have included mentally disturbed individuals inspired by the extremist group — which has in recent months increased its calls for “lone wolves” to act. But other assailants may have maintained at least indirect contact with the extremist group. Adding to the chaos, there have been two additional highly violent attacks in Europe by assailants with no definable political motive at all, including a German-Iranian teen who went on a shooting spree in Munich.

Even the four attacks in two weeks claimed by the Islamic State — two in Germany, and two in France including the slaying of the priest — have been terrifyingly different.

The assailants’ weapons: a truck, an ax, a knife and a bomb.

Their victims: revelers enjoying Bastille Day fireworks, commuters on a Bavarian train, bystanders at a music festival and the priest. The locations: from small towns to the major coastal city of Nice.

The randomness of the attacks, experts say, is making it even more difficult for security services to do their jobs because the potential targets are virtually limitless, as are the means and the profiles of perpetrators.

“It’s a mass diffusion of the phenomenon, and it’s quite worrying that we’re seeing the attacks go in that direction,” said Raffaello Pantucci, a terrorism expert at London’s Royal United Services Institute.