On the afternoon of 17 August 2017, 22-year-old Younes Abouyaaqoub drove a van into a crowd of pedestrians on La Rambla street in Barcelona, Catalonia, Spain, killing 13 people and injuring at least 130 others, one of whom died as a result of the injuries ten days later, on 27 August. Abouyaaqoub fled the attack on foot, then killed another person in order to steal the victim's car and escape. He was later killed by police in Subirats, a town 31 kilometres (19 mi) west of Barcelona, on 21 August.
Nine hours after the Barcelona attack, five more men, thought to be members of the same terrorist cell, drove into another group of pedestrians in nearby Cambrils, killing one woman and injuring six. All five of these attackers were shot and killed by police.
The night before the Barcelona attack, an explosion occurred in a house in the Catalan town of Alcanar, destroying the building and killing two members of the terrorist cell, including the 40-year-old imam, thought to be the mastermind behind the coordinated attacks. The home was found to have contained more than 120 gas canisters, which police believe the cell was attempting to convert into either one large bomb or three smaller bombs, to be transported by rental van and detonated in additional attacks, but that the explosives were accidentally detonated.
The Prime Minister of Spain, Mariano Rajoy, called the attack in Barcelona a jihadist attack. Amaq News Agency attributed indirect responsibility for the attack to the Islamic State. The attacks were the deadliest in Spain since the 2004 Madrid train bombings and the deadliest in Barcelona since the 1987 Hipercor bombing.
A 2022 statement by former Spanish police commissioner José Manuel Villarejo in the Spanish High Court appeared to suggest that the Spanish National Intelligence Service was aware of, and potentially involved in, the attacks. However, others have since dismissed his claim as a conspiracy theory.
Van attack on pedestrians in La Rambla
At 16:56 CEST (UTC+2) on 17 August 2017, Younes Abouyaaqoub drove a white Fiat Talento van onto the pavement of Barcelona's La Rambla, crashing into pedestrians for about 550 metres (1,800 ft) between Plaça de Catalunya and Liceu before stopping on the Joan Miró mosaic. Witnesses said the vehicle zigzagged at high speed down the street, ramming pedestrians and cyclists.
The numerous impacts the van had received caused the airbag to inflate and the driver protection system to automatically shut down the electrical system of the van, causing it to halt. In the confusion, Abouyaaqoub was able to get away. He fled on foot and made his way to the university district before hijacking a car and stabbing the driver to death.
The van used in the La Rambla attack was rented in the neighbouring area of Santa Perpètua de Mogoda, along with a similar van, considered to be a getaway vehicle, and found by 19:00 in Vic. Younes Abouyaaqoub's credit card was used to pay for the van rental.
In a police press conference at 19:00 local time, a spokesperson confirmed the terrorist nature of the event.
Ramming of a police barricade on Avinguda Diagonal
About two hours after the attack on La Rambla, a white Ford Focus rammed a police checkpoint in Avinguda Diagonal, at the exit of Barcelona, leaving an officer of the Mossos d'Esquadra injured. The vehicle fled to a neighboring area, Sant Just Desvern, and the driver abandoned the car near the building known as Walden 7. The police found a man stabbed to death in the rear seat who, they believe, was murdered by the Ramblas driver who had escaped by hijacking the car.
On August 16, the day before the Barcelona attacks, an explosion destroyed a house in Alcanar, with one dead reported and seven injured people. Abdelbaki Es Satty and another man, Youssef Aallaa, died in the Alcanar explosion.
Police initially thought it was an accidental gas explosion, but hours later believed the explosion was caused by stockpiled explosives accidentally going off. A Moroccan man was injured in the explosion and taken to the hospital. The explosive TATP and 120 canisters of butane and propane were found inside the house. Catalan bomb squads carried out a controlled explosion at the property where the gas canisters were stored. There was speculation that the terrorists intended to take trucks loaded with explosives and combustible gas to attack the Sagrada Família.
Police said they were working under the hypothesis that the terrorists shot in Cambrils were connected to the Barcelona attack and Alcanar explosions. Police chief Josep Lluís Trapero believed terrorists were in the process of manipulating the gas canisters when they exploded, after which they decided to continue their plans by conducting more rudimentary vehicle ramming attacks.
A second explosion occurred at the same location during excavation, possibly caused by a spark from a backhoe igniting a gas canister among the debris. At least nine people were injured, with one police officer in critical condition.
At about 21:30 on 17 August, Houssaine Abouyaaqoub, Omar Hichamy, Mohamed Hichamy, Moussa Oukabir, and Said Aalla were seen on a security camera at a local shop purchasing four knives and one axe.
At around 1:00 am on 18 August in Cambrils, the five men drove an Audi A3 automobile into a crowd of pedestrians before it rolled over after crashing with a Mossos d'Esquadra police car conducting a checkpoint at the intersection of Passeig Miramar, Passeig Marítim, and Rambla de Jaume I streets. The crash left one police officer injured. The five individuals inside were wearing fake suicide vests and attacked bystanders with knives. They stabbed a 63-year-old Spanish woman to death and injured six other people in the attack.