The Brussels attacks, following only months after the ones in Paris, revealed that the network of ISIS-affiliated terrorists in Europe was far larger and more coordinated than European officials had realised. It is now clear that dozens of people were involved in preparing, assisting or supporting the attacks; more than 20 people connected to them in some way are thought to be remain at large, according to press accounts, including most notably the third man captured on CCTV at Brussels airport before the bombings. With hindsight, a number of incidents in the last two years that investigators classed as “lone wolf” attacks inspired by ISIS now appear to have been part of a more concerted campaign organised and supported directly from Syria.
It remains unclear whether the network behind the Paris and Brussels attack is matched by others in Europe, or if it was the main channel for ISIS to organise and conduct attacks in this continent. The central role that Abdelhamid Abaaoud, identified by investigators as the ISIS operative in charge of organising attacks in Europe, played in the network suggests it may have been the primary vehicle for ISIS action here. The sophistication of the network’s operations was notable, as shown by its members’ ability to handle combat weapons in Paris, their success in making large-scale bombs with the volatile chemical compound TATP, and their apparently rigorous use of encrypted communications. A large number of the men involved in the attacks had clearly refined these skills in Syria before returning to put them to use in European cities.
Also notable is the cross-European nature of the network’s reach. Law enforcement officials have made arrests of people who are thought to be connected to the network in France, Belgium, Germany, the Netherlands and Italy. Beyond these countries, the men involved in the attacks are known to have travelled at least to the United Kingdom, Austria, Hungary and Greece within the last two years. The picture that emerges is of an interlocking group of radical young men, often with links to criminal networks, almost all with European citizenship, who were able to move freely around the continent as well as back and forth to Syria. A US counter-terrorism official recently described the network as having “a large number [of members], all across Europe”. Fighters returning from Syria were able to tap into existing networks within their communities for help with false documents, transport, safe houses and other logistics.
A part at least of Abaaoud’s network remains in place – and others will arise to replace it. The numbers of European “foreign fighters” in Syria and Iraq gives ISIS a ready supply of candidates who can be trained and sent back to Europe to conduct attacks. A recent study by the International Centre for Counter-Terrorism estimated that around 4,000 Europeans have gone to fight in Syria, of whom a third have returned to their home countries (with France, Germany, the United Kingdom and Belgium providing the majority of fighters). Clearly, counter-terrorism in Europe must focus on this more coordinated and heavily resourced part of jihadist terrorism – recognising that there will always be others who are inspired by ISIS or other radical Islamist groups but lack the capacity to cause serious harm.
In the wake of the Brussels attacks, there has been much attention paid to the flaws of Belgian security services and of European counterterrorism cooperation more broadly. It was obviously a major failing of Belgian authorities not to process and share the information provided by Turkey last year that the future Brussels airport bomber Ibrahim el-Bakroui, who already had a criminal record in Belgium, had been arrested near the Syrian border. The sharing of information within and between European countries has been hampered by weak institutional links, an absence of regular contact, lack of trust and even a failure to agree on a common transliteration of Arabic-derived names. Improving coordination should be an urgent priority, even if the idea of a common European intelligence agency, floated by some politicians, will not win the support of EU member states.
Calls for granting security services greater powers against suspected terrorists, heard in a number of European countries after the Paris attacks, seem like a less constructive avenue to pursue. Security services had already had contact with or know the names of many of the people who have turned out to be involved in Abaaoud’s network, and the intensive security measures put in place in Belgium and France after the Paris attacks in November did not prevent last month’s bombings in Brussels. It is not necessary to widen the scope of those whom intelligence services can track or move against, but rather to bring greater precision and discrimination to the challenge of determining which of the numerous people already under suspicion should be the subject of greatest concern. To do this, security services need above all to cultivate better sources within marginalised Muslim neighbourhoods like Molenbeek in Brussels or the Parisian suburbs – an effort that heavy-handed security measures are more likely to hinder than assist.
Reinforcing controls at the EU’s external borders – as the EU is currently trying to do – would also reduce the ease with which fighters from Syria can slip back into the EU undetected. This is the one way in which the fight against terrorism overlaps with the inflammatory topic of migration – and a greater degree of control might help reduce the association between the two subjects that anti-immigrant groups and political parties are readily exploiting. In fact, the overwhelming majority of those involved in Islamist terrorist plots within the EU are European citizens.
Security officials agree that the fight against terrorist operations like those carried out in Paris and Brussels must be fought on European soil. Nevertheless, in the aftermath of the Paris attacks, EU member states stepped up their military action against ISIS facilities in Syria, presenting this as a form of self-defence. Many European countries are also considering the circumstances under which they would conduct air strikes against ISIS bases in Libya, where the terrorist group has established a significant presence. It is essential for Europeans to be clear about what military action of this sort can – and cannot – accomplish. As part of an integrated approach that includes an offensive by ground forces and a political strategy to resolve civil wars that have allowed ISIS to capture ground, airstrikes can play a constructive role. Military action that takes account of the political context can reduce the territory that ISIS controls and also undermine its propaganda appeal, creating an image of weakness and retreat rather than inexorable advance.
By contrast, airstrikes that are conducted in isolation from a broader strategy may create the political impression within Europe that governments are acting against the terrorist threat, but they will do little to hinder attacks in European cities or to undermine ISIS’ growth on the ground. Instead, ill-thought out military action may undermine political initiatives that could reduce local conflicts (for instance in Libya) and set a precedent for militarised counterterrorism that is ultimately harmful for the international rule of law.
The European Council on Foreign Relations does not take collective positions. ECFR publications only represent the views of their individual authors.