The Barcelona attack is the latest in a series of terrorist atrocities in Europe using vehicles to kill pedestrians in the continent’s largest cities.
At least one person has been confirmed dead and 32 injured by authorities in Spain after a hired van was driven into pedestrians on the city’s popular La Rambla street.
Isis has issued detailed guidance to its followers on how to commit massacres using lorries, vans and cars, as well as instructions on launching stabbings, bombings and taking hostages.
The group has not yet claimed responsibility for the attack in Barcelona, which authorities are treating as a terror attack, but the assault mirrors multiple assaults carried out by Isis militants across Europe.
In July last year, a Tunisian Isis supporter killed 86 people by ploughing a lorry into crowds celebrating Bastille Day in Nice, then in December 12 victims were killed by another Isis militant who drove a lorry into a Berlin Christmas market.
Dozens injured in Barcelona van terror attack
In the first terror attack claimed by Isis in the UK, Khalid Masood drove a car into pedestrians on Westminster Bridge, killing four people before stabbing a police officer to death outside the Houses of Parliament in March.
Another attacker hijacked a lorry and drove it down a high street and into a department store in Stockholm in April, killing five people.
A hired van was used for the first time by the trio of Isis supporters who rammed pedestrians walking on London Bridge in June and then went on a stabbing rampage in neighbouring Borough Market, killing eight people.
A failed terror attack in Paris’ iconic Champs-Elysees later that month saw a car containing guns and homemade explosives ram into a police vehicle, killing an attacker who had left a letter declaring allegiance to Isis inside the vehicle.
All attacks, including the emerging atrocity in Barcelona, have followed evolving instructions issued by Isis through its sophisticated online propaganda machine.
The group has intensified calls for supporters to launch attacks in their home countries in the West as it loses territory in Syria and Iraq and security crackdowns have made reaching the so-called caliphate almost impossible.
The first issue of the group’s Rumiyah propaganda magazine, published in multiple languages in September, declared murdering civilians “halal”, meaning permissible under Islam.
Urging followers not to limit themselves to attacks targeting security forces and politicians, an article claimed massacres were a “form of worship” and any non-Muslim men, women and children were “fair game”.
“This includes the businessman riding to work in a taxicab, the young adults engaged in sports activities in the park, and the old man waiting in line to buy a sandwich,” it continued. “Striking terror into the hearts of all disbelievers is a Muslim’s duty.”
Two months later, the third edition of Isis’ magazine issued detailed guidance on using vehicles in terror attacks, advising militants on how to hire or steal lorries, vans and SUVs to inflict maximum casualties.
Targets identified included “pedestrian-congested streets” and tourist attractions in major cities, with European capitals and nations in the US-led coalition bombing Isis territories singled out.
The article, entitled “just terror tactics”, also advised attackers to fill the vehicle with pieces of paper declaring allegiance to Isis and to “ensure utmost carnage” by carrying a secondary weapon like a gun, knife or explosives.
Subsequent magazines included instructions on how to make Molotov cocktails, napalm and explosives and in May new orders emerged calling for hostage-taking.
A lengthy Rumiyah article said large numbers of victims should be held not “to negotiate one’s demands” but to “create as much carnage and terror” until being killed by police.
Isis called on followers to keep several hostages alive to use as human shields against responding forces, as well as generating publicity to “more effectively plant terror into the hearts of the disbelievers”, citing popular restaurants among targets.
Restaurants and cafes have been the target of several Isis-linked terror attacks, including a hostage taking in Sydney in 2014, suicide bombings in Iraq and Syria, a shooting and suicide bombing in Jakarta and an attack where 22 hostages were massacred at a restaurant in Dhaka in July last year.
There have been no previous terror attacks claimed by Isis in Spain, where almost 200 people were killed by al-Qaeda inspired terrorists in the Madrid bombings in 2004.
Spanish police have arrested several suspected Isis supporters in recent years, including a suspected recruiter detained on Mallorca who was accused of inciting terror attacks.