At least one "Islamist terrorist" was involved in the Monday evening attacks in Vienna, according to Austrian Interior Minister Karl Nehammer. He said that one attacker, a man wearing an explosives belt that turned out to be fake, whom authorities have identified as an Islamic State sympathizer, was killed by police.

Meanwhile, a jihadist cell has reportedly claimed responsibility for the attacks, saying they were carried out in retaliation to Austria's participation in the US-led allied forces' attacks on the Islamic State.

While the claim awaits verification, and an intensive manhunt is still underway for accomplices and any further perpetrators who may be on the run, no conclusive judgment can be made. However, if the Austrian government's initial findings hold true, taking into account the recent heinous attacks in France, a worrisome pattern emerges.

Should the Vienna attacks end up being proven to be what they appear to be, it would be a bloody hallmark of the severity of Islamic extremism in continental Europe, which has obviously ballooned into an outstanding threat to Europe's long-standing peace and security.

Religious freedom and tolerance have been core parts of multiculturalism in the civilized world. But the recent tragedies linked to religious extremists must alert us to the terrorist potential such elements constitute and the need for resolute actions to have them neutralized.

French President Emmanuel Macron's determination to tackle the looming threat has already triggered backlashes. But what happened in his country and now in Austria shows Europe can't afford to wait until it becomes too late.

There may be clamor about a "clash of civilizations". But unless one intentionally confuses a certain civilization with the criminal offenses committed in its name, the fight against terror has nothing to do with civilizations.

All acts of terror must be condemned. No legitimate government should offer safe haven for such criminal elements, or engage in international blackmail taking advantage of their presence.

The attacks in Vienna and those in France have rallied international solidarity across Europe and beyond, driving home the critical message that the civilized world won't be intimidated by terrorists. Instead, such acts of terror should inspire closer international coordination and cooperation aimed at the elimination of terrorism and extremism.