Barcelona attack: Terrorists' 'plan A' was devastating truck bomb atrocity on Las Ramblas, police reveal

Investigators say rushed attacks on Las Ramblas and Cambrils were 'rudimentary compared to original plans

Attackers attempted to hire large lorry before being forced to switch to vans (AFP/Getty)

The terror cell behind two attacks in Spain was planning a far more deadly massacre before an accidental explosion foiled their plans, police have said.

Josep Lluis Trapero, the head of Catalonia’s police force, said investigators believe plotters were preparing multiple assaults for “some time” before their base was destroyed by a gas explosion that killed one person on Wednesday night.

Around 20 bottles of butane were discovered in the ruins of a house in Alcanar following the explosion, which analysts said could have been loaded into a vehicle and combusted in a ramming attack.

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One or more attack was being planned in Barcelona and the perpetrators had material to carry out a much bigger assault, Mr Trapero told a press conference.

“Because of [the explosion in Alcanar] the attack in Barcelona and the one in Cambrils were carried out in a more rudimentary way than originally planned,” he added.

The house was leveled by the explosion (EPA/Jaume Sellart) (EPA/JAUME SELLART)

A second van found in the town of Vic in Catalonia is also being investigated by police amid reports that the attackers may have intended to hire a lorry.

Investigators told the New York Times that they first attempted to hire one from a rental company, but were foiled when the driver failed to produce the necessary permit for an HGV.

If loaded with gas canisters, a lorry could have caused a devastating explosion if rammed into a building at speed, but the attackers were forced to switch to two small vans.

The destruction of the gas canisters in Wednesday’s explosion appears to have disrupted the plot further, resulting in the unsophisticated attack in Barcelona and a second ramming in a Catalan resort town.

Hours later, a police officer shot five suspected terrorists dead after they ploughed an Audi car into pedestrians in Cambrils, with one woman dying of her injuries in hospital.

Officials said the occupants of the car were wearing fake suicide vests and had been armed with an axe and knives to be used as part of the attack. One person was stabbed in the face before they were shot dead.

The method closely follows guidance issued by Isis on what it calls “just terror tactics”, which advises followers to hire lorries and other large vehicles to run over victims in crowded public places.

Updated orders issued earlier this year urged attackers to have a secondary weapon in the vehicle like a gun, knife or explosives to continue the massacre after crashing, and included instructions on how to make incendiary devices.

The advice has been echoed in the attacks in Nice, Westminster, Berlin, London Bridge.

A foiled plot in Paris last year saw Isis supporters load a car with gas canisters, while a man died in June after ramming a car full of explosives into police on the Champs-Elysees, and a lorry attacker in Stockholm had put an explosive device in the front seat that failed to properly explode on impact.

Isis has claimed responsibility for the attack in Barcelona, saying it was carried out by “soldiers of the Islamic State” responding to calls to target countries in the US-led coalition bombing its territories in Syria and Iraq.

Police have not identified any of the dead suspects but Mr Trapero said investigators were looking into the possibility that the man who drove the van in Barcelona could have been among them.

“We are investigating whether one of the people shot dead in Cambrils might be the driver [of the van in Barcelona] but at the moment we don’t have any confirmed information,” he said.

“We are analysing footprints but we don’t yet have all the analysis so we are going through the process.

“It could be one of the people that was shot in Cambrils – we don’t know yet but hopefully the investigation will clarify this later.”

He said the driver of the van used in the Barcelona attack has not yet been formally identified, amid local reports that police are hunting 18-year-old Moussa Oukabir, whose brother claimed stole his ID to hire the vehicle.

Mr Trapero said the number of people under investigation, reported to be around a dozen, “keeps changing” and that a separate incident where a car drove into a police checkpoint is not being treated as linked.

Four people have been arrested so far, one in Alcunar and three in Ripoll.

Three are Moroccan nationals and one is Spanish, while none have a criminal background linked with terrorism.

“Their profile in general is a young person, the youngest was 21, and the others are 28, 34 and 27 years old,” Mr Trapero said, adding that officers are working to identify the suspects based in Alcanar and inside the car in Cambrils.

Moussa Oukabir, from Barcelona, is the brother of arrested suspect Driss Oukabir (Kiwi)

As the investigation continues, he urged people not to gather en masse in public unless it is at an official event under protection from security forces.

Carles Puigdemont, the head of the Catalan government, praised thousands of people in Barcelona who started spontaneous chants of “I am not afraid” following a minute’s silence on Friday.

“We will win this battle against terrorism ... with solidarity, freedom and respect,” he said.

“These terrorist attacks have tried to break the way we understand and live life but the answer we have seen this morning has been the return to normality, without fear.”

Mariano Rajoy, the Prime Minister, said all of Spain’s political parties are uniting to combat terrorism and will “have the same attitude of victory towards vanquishing terrorism ... we have had enough attacks.”

He says the “global battle” will be fought by all countries that defend democracy, freedom and human rights.

Mr Rajoy has attended a meeting of Spain’s crisis cabinet with interior ministry and security officials and another meeting is scheduled for tomorrow, where the country’s terror threat level will be assessed.