ISIS Has Now Become a Truly Global Threat

The Islamic State of Iraq and Greater Syria (ISIS)’s claim of responsibility for the deadly bombings in Brussels on Tuesday was a harrowing reminder of the group’s reach and ambitions throughout not just the Middle East, but Europe and beyond.

The claim of responsibility was published by ISIS’ official news agency on Tuesday. The fighters targeted Brussels’ Zaventem airport and a metro station in the city due to Belgium’s “participating in the coalition against the Islamic State,” the statement said, according to news reports.

The Brussels attack illustrates once again the intensity of the Islamic State’s desire to carry out attacks on civilians far beyond the ground under its control. When it first emerged, seizing large areas in Iraq and Syria in 2013 and 2014, ISIS set itself apart from other international jihadist groups, such as al-Qaeda, which never controlled territory even remotely on the same scale.

But today, it appears to have two robust prongs — both a proto-state in lands that it has captured in Iraq and Syria; and also an emergent international network, comparable to that of al-Qaeda.

And as the group loses ground in Iraq and Syria, it appears ever more bent on launching deadly attacks outside its areas of control. Over the last five weeks, ISIS has claimed bombings in the Baghdad area and the cities of Damascus and Homs in Syria, launched an armed assault on a town in Tunisia, and has been linked to a suicide bombing in a central district of Istanbul. Together, these assaults have killed hundreds of people.

To carry out these attacks and more, ISIS has recruited a sizeable number of European-born fighters among its estimated 11,000 foreign recruits, according to the International Center for the Study of Radicalization in London. ISIS has recruited more people per capita from Belgium than from any other European country.

Read more: Brussels Bombing Reveals Europe’s Security Dilemma

Thomas Hegghammer, an expert on terrorism in Europe and a senior fellow at the Norwegian Defence Research Establishment, says Europe now represents a “complex landscape” of jihadist threats. “[There are] returning foreign fighters who are potentially easier to find, but they strike harder if you don’t find them. You have sympathizers, who in general don’t carry out as lethal attacks but they’re harder to find. And then you have al Qaeda on the side,” he said. “The resources of the services are spread thin across these very different types of threats.”

The attacks in Paris in November, the starkest example before Tuesday of ISIS-orchestrated terror in Europe, demonstrated a new level of sophistication: According to official documents reviewed by The New York Times, the attackers took extreme precautions to conceal their communications, brewing their own explosives, and carrying out attacks on several targets simultaneously. The suspected planner of the Paris attacks, Belgium-born Abdelhamid Abaaoud, joined ISIS in Syria before reentering Europe.

The attacks come as ISIS continues to lose territory in its self-declared “caliphate.” Even though it maintains control of Mosul, Iraq’s second largest city, the size of the group’s territory in that country and in Syria shrunk by 14 percent, according to the conflict-monitoring firm IHS.

Read more: Why ISIS is Going Broke

In Iraq, ISIS recently lost the city of Ramadi to U.S.-backed Iraqi troops in December. The month before, Kurdish and other forces reclaimed the town of Sinjar, cutting the jihadists critical supply line to Syria. Inside Syria, ISIS has lost ground both to the Syrian regime and to U.S.-backed Kurdish and Arab forces, even as its command center in Raqqa endures.

But the latest assault on Brussels shows that the group’s ambitions remain intact, and its corps of European footsoldiers on the loose and ready to strike.