Beyond Brussels: ISIS Sleeper Cells Are Europe’s New Reality

Why ISIS sleeper cells can lay low across Europe, and emerge to unleash terror undetected

The wanted notice of terrorist Salah Abdeslam (L) and Mohamed Abrini — AFP/Getty Images
Mar 23, 2016 at 4:33 PM ET

Four months of raids and arrests by Belgian counterterrorism officials could not stop the deadly blasts in Brussels that killed at least 31 people and left more than 270 injured on Tuesday. 

The attacks, claimed by ISIS and possibly plotted soon after the carnage in Paris unfolded last November, are the latest evidence of deepening jihadists networks in parts of Europe. They also reveal the severe limitations law enforcement faces as it confronts an emerging reality on the continent: small bands of Islamist militants are increasingly able to launch devastating strikes in cities outside the terror group’s territory. And the threat extends far beyond Belgium, Europe’s “Capital of Terrorism,” multiple experts told Vocativ. 

Here’s why.

More ISIS Has Long Had Brussels In Its Crosshairs

Belgium and its neighbors have a high number of homegrown radicals

Long a hotbed for jihadists, Belgium has seen a larger share of its Muslim population travel to fight in Syria than any other country in the West. Neighbors such as Denmark and the Netherlands have also produced scores of jihadists who have filled the ranks of ISIS and other extremist groups, which experts say indicates a fertile breeding ground for militants back home.

The high number of potential homegrown radicals has completely overwhelmed local law enforcement and counterterrorism operations. “The main shortcomings arise from the asymmetric nature of a small country facing a significant radicalization problem,” Nicholas Glavin, terrorism researcher at the U.S. Naval War College, told Vocativ. “Belgian special operations units, while highly effective, simply do not have the capacity to thoroughly counter such a large threat with disproportionate resources.”

A Belgian counterterrorism official told BuzzFeed News“We just don’t have the people to watch anything else and, frankly, we don’t have the infrastructure to properly investigate or monitor hundreds of individuals suspected of terror links, as well as pursue the hundreds of open files and investigations we have.”

“It’s literally an impossible situation and, honestly, it’s very grave,” he added.

Terror cells can go months without detection

That helps to explain, in part, why officials in Belgium were unable to disrupt a suspected ISIS-linked terror cell in Brussels prior to November’s attacks in Paris, which killed 130 people. Or why it took authorities in the country until last week to capture Paris suspect Salah Abdeslam, who hid for more than 120 days in Brussels’ Molenbeek district. Analysts say it also meant that Belgian law enforcement failed to prevent the bombings of Brussels’ airport and metro system on Tuesday, despite the attacks likely taking months to plan. “Plots like this take weeks or months to put in motion,” William McCants, a terrorism analyst with the Brookings Institution, told Business Insider. “If the attackers are associates of Abdeslam, then they probably moved up the timetable of a preexisting plot to avoid capture.”

Experts told Vocativ that the terror cells behind Brussels and Paris were likely comprised of, at most, a few dozen facilitators and supporters. With thousands of ISIS militants coming from Europe, the potential threat is widespread. “When you have these large numbers of foreign fighters, ISIS can cherry-pick the best ones to give them training and dispatch them to their home country to carry out attacks,” Bruce Hoffman, a terrorism expert and director of Georgetown University’s Center for Security Studies, told the Washington Post. “Even if ISIS dispatches only 10 percent of these fighters, you’ve got the foundation of a potentially highly effective terrorist cell and support network.”

More ISIS Propaganda Strategy: Beyond Beheadings And Elaborate Executions

Lax borders and intelligence-sharing intensify the threat

Europe’s open borders and its persistent problems with intelligence-sharing among countries are a boon for the types of terror cells that orchestrated the attacks in Brussels and Paris, experts said. Belgium provides a case study in how ISIS-linked groups can exploit countries that have weaker surveillance networks and counterterrorism machinery. Ultimately, countries that have the fewest resources for counter-terror capabilities can become the breeding grounds and launchpads for strikes elsewhere on the continent.

“The problem with Europe is that it’s open for terrorists and closed for counter-terrorists,” Clinton Watts, a senior fellow with George Washington University’s Center for Cyber and Homeland Security, told Vocativ. He added: “There’s no FBI-like capability in Europe. It would be the same if every state and local police department in U.S. had to work together to run somebody down.”

ISIS thrives in this environment

Unlike other jihadists groups, ISIS-linked cells have been largely decentralized. Their terror plots do not require meticulous planning, coordination or approval from the group’s top officials—a hallmark of al-Qaeda operations under Osama bin Laden—which makes them harder to detect, analysts said. ISIS’ penchant for soft targets and indiscriminate violence also lowers the threshold for militants set on an act of terror.  “ISIS isn’t trying to be too complicated,” said Patrick Skinner, a terrorism analyst with The Soufan Group, a security consulting firm. “They’re operating within general parameters and they put the plots together on their own. With right training, these guys on autopilot.”

More The Real Power Of ISIS: Inspiring Terrorism Like San Bernardino

A dangerous new paradigm in Europe?

Some experts fear that Brussels could set a dangerous new precedent for jihadists in Europe. Instead of targeting France, the United Kingdom or Spain—countries with marquee cities like Paris, London or Madrid, but also more robust intelligence communities—Tuesday’s attacks show a willingness among ISIS-linked operators to strike where the continent is most vulnerable in lieu of a more spectacular operations. “All it takes is a place with a high number of foreign fighters, an affinity for ISIS and a country with small counterterrorism capacity and capability,” Watts said. The bad news? These types of targets go beyond Belgium and include other countries such as the Netherlands or Denmark. “If they’re hit, we’ve got a huge problem.”