The attack lasted 10 minutes, from 7:50 to 8:00 p.m. on Tuesday evening, and targeted shoppers in Christkindelsmärik, a large Christmas market held annually in Strasbourg. The lone shooter, who has since been identified as Chérif Chekatt, a French citizen, was reportedly heard shouting “Allahu Akbar” (God is great) repeatedly as he opened fire on the unsuspecting shoppers. He also tried to stab some of them using a knife. Chekatt eventually exchanged fire with French soldiers and officers of the National Police before fleeing the scene of the attack in a taxi cab. Three people were declared dead at the scene, while 12 others were urgently transported to nearby hospitals. Six of them remain in critical condition. Chekatt remained at large until Thursday evening, when he was shot dead by police in Strasbourg.

It is important to stress that the choice of Strasbourg as the site of the terrorist strike was not accidental, nor was the attack spontaneous. A city and of nearly 500,000 inhabitants in its greater district, Strasbourg is one of the European Union’s de facto capitals. It hosts several European institutions, including the building of the European Parliament. Its geographical location on the French-German border epitomizes the crossroads of Franco-German cultural traditions. Its distinct character symbolizes the coexistence of Europe’s two leading powers, which forms the cornerstone of the European Union project. The majority of Strasbourg’s residents are bilingual and communicate in Alsacien, a peculiar mixture of French and German. The city also exemplifies a distinctive brand of 21^st-century Christian unity through the balanced coexistence of Catholic and Protestant religious cultures. The Christkindelsmärik —the venue that was attacked on Tuesday— is Europe’s largest Christmas market and symbolizes precisely that coexistence. Providing that Tuesday’s attack was sanctioned and/or planned by the Islamic State or one of its affiliate organizations, its strong symbolism is apparent.

As Washington Examiner commentator Tom Rogan noted on Wednesday, it appears that the perpetrator of the attack was able to acquire a semi-automatic weapon, as well as grenades. Unlike the United States, accessing these types of weapons in Western Europe is exceedingly difficult. This is so especially in France, a country that has remained in a perpetual state of heightened security since the Paris attacks of November 2015. It is even more perplexing that Chekatt was able to acquire this type of weaponry, given that his name featured on the terrorism watch lists of France’s security and intelligence services. Additionally, says Rogan, one of the operational trademarks of the Islamic State centers on adhering to a sharp division between its arms procurement networks and the individuals who carry out terrorist attacks. This means that a wider Islamist network in France, Switzerland or Germany, was able to armed and possibly trained Chekatt in Europe, since the attacker is not believed to have visited the Middle East or North Africa.

Rogan also points out that Chekatt —a French-born 29-year-old petty criminal— was radicalized while serving time in prison. This raises important questions about Salafist-Jihadi radicalization networks inside Western European prison systems. The security implications of this realization inevitably widens the security considerations of Europe’s counterterrorism agencies. The latter have so far focused primarily on the danger posed by the return of European Islamic State volunteers from the Middle East. The problem, however, appears to be more complicated.

Ultimately, the Strasbourg attack demonstrates that, despite several years of concerted efforts, the ability of European counterterrorism agencies to prevent strikes by Islamist groups on European soil is limited. Meanwhile, European streets are busy during the Christmas season, with indoor and outdoor markets and festivals, concerts, as well as a host of religious observances taking place in thousands of different locations across the continent. Should Tuesday’s attack in Strasbourg mark the beginning of a sustained terrorism campaign by the Islamic State, December could prove to be a deadly month in Europe.