BARCELONA // Spanish security forces were hunting the driver of the van who escaped after ploughing into crowds thronging Barcelona's most famous thoroughfare killing 13 people in the deadliest of a series of planned attacks. Spanish named the man as 18-year-old Moussa Oukabir, whose brother was detained after his documents were used to rent the van that weaved down Las Ramblas mowing down tourists and stalls. Driss Oukabir handed himself in after police released his image and claimed that his brother stole his documents. Officials said at least one person was still being sought over the attack claimed by ISIL in Las Ramblas, which was packed with tourists taking an afternoon stroll. As security forces hunted for the van's driver, who was seen escaping on foot, police said they had <a href="https://www.thenational.ae/world/europe/barcelona-terror-attack-police-kill-suspects-in-cambrils-to-foil-second-attack-1.620732">killed five attackers on Thursday night in Cambrils</a>, a town south of Barcelona, to thwart a separate strike using explosive belts. Six civilians and a police officer were injured in Cambrils when the attackers ran them over in a car, before police shot them dead and carried out controlled explosions. Officials said Friday that the explosive belts were well-made fakes. Police said the Cambrils incident was linked to the van attack in Barcelona. Before the van ploughed through Las Ramblas, one person was killed in an explosion in a house in a separate town south-west of Barcelona, police said. Residents there were preparing explosives, a police source added. Police have arrested three people over the Las Ramblas attack. The two arrests on Thursday did not include the driver of the van. The first two were a Moroccan and a man from Spain's north African enclave of Melilla. They added that the situation in Cambrils was under control. Eight people were suspected to have been part of a cell behind the Barcelona attack, Catalonia Interior Minister Joaquim Forn told local radio on Friday. "The priority right now is work out the identity of these people, to prove and show the relationship between the different people involved, those that took the van and those that have been able to escape," Mr Forn said. Witnesses to the van attack said the white vehicle had zigzagged at high speed down Las Ramblas, ramming pedestrians and cyclists, sending some hurtling through the air and leaving bodies strewn in its wake. The injured and dead came from 24 different countries, the Catalan government said on Friday in a statement, ranging from France and Germany to Pakistan and the Philippines. ISIL's Amaq news agency said: "The perpetrators of the Barcelona attack are soldiers of ISIL and carried out the operation in response to calls for targeting coalition states" - a reference to a US-led coalition against the militant group. Spain has several hundred soldiers in Iraq providing training to local forces in the fight against ISIL, but they are not involved in ground operations. The ISIL claim could not immediately be verified. If the involvement of ISIL militants is confirmed, it would be the latest in a string of attacks in the past 13 months in which they have used vehicles to bring carnage to the streets of European cities. <strong>Read more: <a href="https://www.thenational.ae/world/how-vehicles-became-the-new-weapon-of-terror-1.620765">How vehicles became the new weapon of terror</a></strong> That modus operandi - crude, deadly and very hard to prevent - has killed well over 100 people in Nice, Berlin, London and Stockholm. British tourist Keith Welling, who arrived in Barcelona on Wednesday with his wife and nine-year-old daughter, said they saw the van drive past them down the avenue and took refuge in a restaurant when panic broke out and the crowd started running. "People were shouting and we heard a bang and someone cried that it was a gunshot ... Me and my family ran into the restaurant along with around 40 other people. "At first people were going crazy in there, lots of people crying, including a little girl around three years old." It was the deadliest attack in Spain since March 2004, when Al Qaeda militants placed bombs on commuter trains in Madrid, killing 191 people and wounding more than 1,800. Spanish prime minister Mariano Rajoy announced three days of official mourning for what he called a "jihadist attack". The Spanish royal household said on Twitter: “They are murderers, nothing more than criminals who are not going to terrorise us. All of Spain is Barcelona.” US president Donald Trump said: "The United States condemns the terror attack in Barcelona, Spain, and will do whatever is necessary to help." He added: "Be tough & strong, we love you!" <strong>Barcelona terror attack: <a href="https://www.thenational.ae/world/barcelona-terror-attack-international-figures-unite-in-condemnation-1.620781">International figures unite in condemnation</a></strong> The authorities said two of the men were detained in Ripoll and a third in Alcanar, both in the region of Catalonia, of which Barcelona is the capital. The explosion was also in the town of Alcanar, in the early hours of Thursday. One person died and another was injured in that incident, police said. Police said they also shot dead on Thursday a man who had driven a car into a police checkpoint in Barcelona, though they had no evidence he was connected with the van attack. Mobile phone footage showed several bodies strewn along the Ramblas, some motionless. Paramedics and bystanders bent over them, treating them and trying to comfort those still conscious. Around them, the boulevard was deserted, covered in rubbish and abandoned objects including hats, flip-flops and a pram. Belgium's foreign minister said a Belgian was among the dead. Regional head Carles Puigdemont said people had been flocking to hospitals in Barcelona to give blood. Susana Elvira Carolina, 33, who works at a shop on Las Ramblas, had just entered her building when the van struck. "We had a window and you could see the bodies lying from there, you could see how people were run over ... We were shutting down the blinds but people kept coming in and we had to keep it open so they could enter the shop." <strong>Barcelona terror attack: </strong><a href="https://www.thenational.ae/sport/tennis/nadal-shattered-and-muguruza-shocked-by-barcelona-attack-1.620786"><strong>Nadal shattered and Muguruza shocked by attack</strong></a> The incident took place at the height of the tourist season in Barcelona, which is one of Europe's top travel destinations with at least 11 million visitors a year. Theresa May, Britain’s prime minister expressed a message of solidarity, saying that the UK stands with Spain against terror. The United States’ Secretary of State Rex Tillerson said his country was committed to tracking down terrorist. "Terrorists around the world should know that the United States and our allies are resolved to find you and bring you to justice," he said. While President Donald Trump offered his assistance to authorities in Spain on Twitter. He tweeted: "The United States condemns the terror attack in Barcelona, Spain, and will do whatever is necessary to help. Be tough & strong, we love you!" Outside of politics, Spain’s royal court have condemned the incident, calling the perpetrators “murderers” in a statement released on the royal family’s official Twitter account. The message- translated into English- read: “They are murderers, just criminals who will not terrify us. All Spain is Barcelona. Las Ramblas will be back to everyone.” King Abdullah II of Jordan also sent a message of condolence via his official social media account. The Royal Hashemite Court tweeted: “His Majesty King Abdullah II condemns the deadly attack in #Barcelona #Jordan.”