Strategic Analysis Of Barcelona Terrorist Attack

IISS Strategic Comments

The Barcelona Terrorist Attack

On 17 August, the worst terrorist attack in Spain since the 2004 Madrid train bombings, which killed 191 people, occurred in Barcelona on Las Ramblas, the famously upbeat Catalan city’s central pedestrian promenade. The attack itself killed 14 people and injured at least 100 others; the attacker stabbed another man to death while hijacking his car and escaping in it; and another person was killed in a linked incident in Cambrils a day later. As in the attack in Nice in July 2016 and subsequent ones elsewhere in Europe, men drove large vehicles into crowded areas frequented by foreigners. People from more than 24 countries were killed or hurt. Of the 16 fatalities, six were Spanish, three Italian, two Portuguese, one Belgian, one Australian-British, one German, one American and one Canadian; two were children. The targeting thus appeared to reflect the terrorists’ ruthless indiscriminateness, as well as their desire to degrade Spain’s appeal as a tourist destination and thereby damage its economy.

Shortly after the attack, the Islamic State, also known as ISIS or ISIL, took credit for it, proclaiming that its ‘soldiers’ had again responded to its exhortations. This characterisation suggested that ISIS central command in the Middle East had merely inspired or endorsed the Barcelona attack, and had not planned or directed it. The Spanish people and government have been especially earnest and effective in rejecting Islamophobia, both in general and in the wake of the Barcelona attack; the alienation of Muslim communities does not appear to be as severe in Spain as in some other European countries. Nevertheless, the attack highlights Spain’s standing vulnerability to jihadist terrorism and illuminates other troubling factors.

The plot

Notwithstanding the apparently home-grown nature of the attack, it was apparently an element of a larger plot that was to be executed by a cell of around a dozen people, and thus a more sophisticated operation than the five previous jihadist vehicle attacks that occurred in Europe, starting with the rampage in Nice. Terrorist attacks, of course, are rarely perpetrated by genuine ‘lone wolves’; usually, even ostensibly autonomous culprits are discovered after the fact to have reached out to a larger terrorist organisation for affirmation, if not operational assistance. But the jihadist vehicle attacks mounted in Nice, Berlin and Stockholm, and the two in London involved only one or two primary assailants and, in some cases, only a few other support operatives who helped coordinate or facilitate the attack. The Barcelona plot had more moving parts, and operatives in at least three locations.

On 16 August, the day before the Barcelona attack, an explosion destroyed a house and killed two men in Alcanar, roughly 160 kilometres southwest of Barcelona. One of the dead was Abdelbaki Essati, a 45-year-old imam and the probable leader of the cell that carried out the Barcelona attack. The Spanish authorities believe that the terrorists were using triacetone triperoxide (TATP) to construct a large car bomb when the explosive detonated accidentally. TATP is highly unstable and has been widely used by ISIS, including in attacks in Paris and Brussels. In the house in Alcanar, police recovered a green book with a piece of paper referring to ‘the soldiers of the Islamic State in the land of Andalus’ – the Moors’ term for the territory they occupied in the Iberian Peninsula in the eighth century and partially held until 1492, which jihadist groups have expressed an intent to reclaim. The police also found several tickets for planes to Brussels.

In the attack in Cambrils, a coastal-resort town around 120km southwest of Barcelona, five men drove a car into a group of people, killing one person. After the vehicle overturned, men emerged wearing what would later be determined to be fake explosive belts. Police officers, who had been placed on high alert across the region after the Alcanar explosion and the Barcelona attack, immediately shot all of them dead. On 21 August, the police, acting on a tip, killed Barcelona van driver Younes Abouyaaqoub in a shootout in vineyards in Subirats, around 45km west of the city. Two of four suspects who were initially detained – Mohamed Houli Chemlal and Driss Oukabir – have been charged with terrorism offences. Several members of the cell purchased four knives and an axe between the Barcelona and Cambrils attacks, suggesting that they may have intended to follow up the latter vehicle attack with stabbing sprees along the lines of the Borough Market operation in London last June.

The cell

It has become common for even terrorist attackers known to the police – as a result of previous arrests, investigations or alerts – to thwart the attempts of intelligence and law-enforcement agencies to track them and prevent their operations. Yet most of the members of the terror cell responsible for the Barcelona attack seem to have been ‘cleanskins’ – that is, operatives unknown to the authorities before the attack. The cell consisted of at least 12 men, and was apparently formed and led by Essati in the small Spanish town of Ripoll, around 100km north of Barcelona. Most of the cell’s members were under 25, had jobs and were from seemingly well-assimilated Spanish-Moroccan families. They were reportedly from stable homes, with backgrounds free of domestic violence, ostracisation, prison terms or any additional characteristics typical of radicalised terrorists. Some partied and smoked marijuana. None of them appears to have travelled to a Muslim-majority country for training or other instruction. Yet they had evidently planned the attacks for more than a year, and were prevented from killing vastly more people only by the accidental explosion in Alcanar.

According to officials, Essati had terrorist connections, having been suspected of recruiting jihadists to fight in Iraq in 2006 and of befriending Rachid Aglif, one of the perpetrators of the 2004 Madrid train bombings, during a prison term for drug offences that started in 2010. In 2015 a judge overturned an order to expel Essati from Spain upon his release from prison on the grounds that he had gained employment and made ‘an effort to integrate’. US intelligence agencies believe Essati had strong connections with members of the external-relations unit of ISIS. Among the other members of the cell, only Houssaine Abouyaaqoub had shown signs of radicalisation, as he abruptly turned towards religious conservatism a month before the attacks. Essati seems to have been a charismatic, discreet and highly effective recruiter. He went to live in Ripoll more than a year before the attacks, began to preach at a local mosque and expeditiously formed the cell. While family ties are common in terrorist cells – the units involved in both the Paris and the Brussels attacks included brothers – Essati’s group was unusual in that it included four sets of brothers.

His perhaps uniquely intimate approach to recruitment was clever and effective, broadly in line with long-standing al-Qaeda prescriptions. It yielded a closely knit group whose family ties created a built-in resistance to betrayal. The cell largely functioned below the radar of law-enforcement and intelligence agencies – notwithstanding the state of heightened alert prompted by previous attacks – and had the collective will to complete its mission despite the loss of its spiritual and operational leader to an accident. Radicalisation also appears to have been accomplished by personal contact among individuals who knew one another – most had attended the same middle school or secondary school – as opposed to, say, the internet, rendering the process relatively hard to trace.


Like those of France, Germany, Italy and the United Kingdom, Spain’s security services are experienced in counter-terrorism. They faced persistent ethno-nationalist or ideological terrorist groups before global jihadism took hold, and are capable of mitigating the apparently growing threat of comparatively large and sophisticated ISIS-linked cells. Since the rise of global jihadism, Spain has adjusted well to new threats. Its security agencies have foiled many terrorist plots and arrested more than 700 terrorism suspects since 2004. Enhanced anti-terrorism legislation now permits the Spanish authorities to arrest suspects at an earlier stage of attack planning than in the UK and other EU countries. More particularly, the Spanish authorities coordinated with their Belgian counterparts on an investigation into Essati after he travelled to Vilvoorde, a known target for jihadist recruiters, in early 2016, around the time of ISIS attacks in Brussels – although the probe uncovered no further terrorist links. But the compulsion of ISIS and its followers to conduct mass-casualty attacks makes the stakes of even a single intelligence failure extraordinarily high, as many nations have learned over the past 15 years.

Furthermore, even for highly capable security services such as Spain’s, while raw technical and human intelligence can be collected relatively quickly, processing it into actionable threat information takes time and may not allow for sufficient tactical warning. Before the 2005 London Underground and bus bombings, the UK authorities had access to closed-circuit-television footage of several of the culprits acting suspiciously, but could not examine it in real time. Several perpetrators of the November 2015 Paris attacks were on watch lists or actively sought by police, yet were still able to move around undetected.

The Barcelona operation introduces several factors that could further complicate counter-terrorism efforts in Spain and other European countries. Firstly, the cell that perpetrated the Barcelona attack appeared to combine vehicle attacks – crude operations that call for no special planning or technical capabilities – with more complex terrorist operations requiring significant expertise and coordination. This is a new development, constituting a major challenge to intelligence and law-enforcement agencies. Precisely because of their simplicity and relative spontaneity, vehicle attacks are very hard for police to spot in advance and interdict. This factor puts the onus on intelligence agencies to identify individuals and groups that warrant investigation well in advance of a planned attack, to facilitate its prevention. Secondly, given the Barcelona cell members’ relatively clean records, European and other authorities already burdened with sifting the potential threats from thousands of people on various watch lists will now have to expand their prioritised activities to identifying potential terrorists who do not appear on such lists.

Thirdly, the Barcelona operation makes clear that Spain’s lack of involvement in the US-led anti-ISIS campaign in the Middle East has not inoculated it against jihadist terrorism. Rather, Spain is a live target due to its status as the historical site of spurned Muslim rule; its large and sometimes dissatisfied Muslim population; its testy post-colonial relationship with Morocco; and its proximity to North Africa. Fourthly, although Catalonia has for some time been considered ripe for terrorist recruitment – due to the large number, and disaffection, of Muslim immigrants living in the region – the recent attacks there, like the one in Nice, were launched in locales previously untouched by jihadist terrorism. The terrorists’ enlargement of their area of operations could further stretch counter-terrorism resources. Fifthly, the Barcelona attack has raised recriminations and tensions between Madrid and the autonomous Catalan law-enforcement agency, Mossos d’Esquadra, with the latter pressing for a direct channel to the CIA and other foreign-intelligence services. Such bickering could diminish counter-terrorism effectiveness.


As shown by the Barcelona cell, ISIS-inspired leaders are able to enlist dedicated home-grown jihadists who require little foreign indoctrination. This phenomenon suggests that Muslims’ socio-political situation in Europe makes them susceptible to recruitment in place, even though ISIS has lost territory and political traction in Libya, Iraq and Syria, and has dispersed geographically as a consequence. But these losses and dispersion also mean that the number of jihadists from Europe returning to the continent, and of jihadists indigenous to the Middle East taking refuge in Europe, will likely rise. Many of them will not be inclined to abandon the jihad. Although ISIS leader Abu Bakr al-Baghdadi’s hopes of planting a caliphate in the Middle East have dimmed, ISIS appears all the more determined to stay relevant and conspicuous by inspiring and facilitating out-of-area terrorist attacks. Therefore, Spain and other southern European countries – as transit hubs for jihadists travelling from and through North Africa, and as fertile ground for indigenous recruitment – will contain a growing pool of potential terrorists. Intra-European and broader international intelligence and law-enforcement cooperation, of course, will remain operational priorities. But because the Barcelona cell achieved an unusually high standard of indigenous recruitment, security agencies may also need to refocus on anti-radicalisation efforts and broader reforms aimed at addressing the root causes of terrorism.

Volume 23, Comment 30 – August 2017

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