The suspected jihadists who mowed down walkers in Barcelona city centre and Cambrils had tried to rent a large truck but did not have the correct permit, it has been reported.
They also planned to use explosives to maximise the number people they could kill, a counter-terrorism has claimed.
It has also been claimed that a cell of twelve people may have been involved in the attacks on Barcelona and Cambrils – and that they were planning to use gas canisters to kill victims.
Thirteen people were killed and more than 100 wounded when a van was driven into walkers on the busy Las Ramblas street in Barcelona.
The hired van (pictured), registered to rental company Telefurgo, rammed into scores of holidaymakers and their children before police swooped. It is believed the suspected jihadist plot originally included the use of a large truck and explosives designed to maximise the death toll
Pictured: A man lying on the street in Barcelona after the van ploughed into pedestrians along Las Ramblas
Moussa Oukabir, 18, who lives in Barcelona, has been named as a suspect in the attack after reportedly stealing his brother’s documents
Driss Oukabir (pictured) has been arrested by police, according to local media reports. The Guardia Civil previously said the van used in the attack was rented by Oukabir in the town of Santa Perpetua de la Mogada
Pictured: A man sits on the pavement with his head in his hands after the tragic attack, now being treated as a terrorist incident
In a second attack eight hours later, a car rammed into people in Cambrils – about 75 miles south of Barcelona – and wounded six people before the five attackers were shot.
But the New York Times has been told that the terror plot originally involved the use of a large truck and explosives.
A counter-terror expert told the paper: ‘Part of the plan was they tried to rent a larger truck, but they didn’t have the right permit.’
As a consequence, they ended up renting much smaller vehicles – including the white Fiat van photographed with a crumpled bonnet after the devastating slaughter in Las Ramblas.
Pictured: Armed policemen arrive in a cordoned-off area after a van ploughed into a crowd in Barcelona
At least 13 people have been killed and dozens injured after a van ploughed into pedestrians in Las Ramblas, Barcelona’s busiest tourist area. Police are still hunting two armed men who have escaped and are believed to be hiding in a nearby restaurant
Police are today hunting for Europe’s most wanted man Moussa Oukabir, an 18-year-old Moroccan-born teenager believed to have been the driver during the Barcelona attack.
He fled on foot and it is unclear if he joined the Cambrils attack eight hours later.
His brother Driss Oukabir’s ID was used to rent up to three vans including the one in the attack, but he has handed himself into police and denied any involvement.
Investigators believe the Barcelona atrocity is linked to an explosion at a home 70 miles away in Alcanar which happened 24 hours earlier.
Horrifying images of the aftermath show an elderly couple were among the injured after the van ploughed into pedestrians on the busy Barcelona street
Two suspects were arrested yesterday evening, a Moroccan and a Spanish national, but neither of them was at the wheel of the van.
In Barcelona, officials warn the death toll is likely to rise, with at least 10 people critically injured in yesterday afternoon’s atrocity in the heart of the city’s tourist district.
In the aftermath of the attack police circulated an image of Driss Oukabir, a 28-year-old Catalan resident of Moroccan origin, saying he had rented out a second van thought to be intended as a getaway vehicle – where his documents were found.
But police sources said Oukabir later handed himself in at a police station in Ripoll, 65 miles north of Barcelona, claiming his brother had stolen his documents.
There were harrowing scenes in Barcelona after the van was driven into pedestrians in Las Ramblas in the heart of the city
Hundreds of people can be seen in Barcelona city centre after the horrifying incident
His brother is named Moussa Oukabir, 18, who lives in Barcelona, El Pais reports.
Disturbing comments posted on social network Kiwi by an account carrying Moussa Oukabir’s name and photograph makes reference to killing all infidels.
Horrifying pictures and video from the scene of the Las Ramblas attack show armed police and paramedics rushing around the busy promenade in the centre of the city, as victims lie hurt in the street.
Video has emerged seeming to show a police officer lying on the ground injured in Sant Just Desvern, on the outskirts of Barcelona, after a Ford Focus drove through a roadblock.
Eyewitnesses reported seeing people running away and screaming after the terror attack happened.
Steve Garrett was in a nearby market and sheltered in a bakery with several others after streams of people ran inside.
He told the BBC: ‘A very large number of people ran into the market area in a big kind of way, lots of screaming, lots of shouting.
‘The security guards immediately responded. We ran into the bakery with four or five other people and ran straight upstairs and hunkered down whilst an enormous wave of people went through the market.
‘Obviously coming from England it was reminding me a great deal of what happened in London, so we were very concerned about what might be going on next.’