Police say the terrorists who carried out dual attacks in Barcelona and Cambrils in Spain were planning a far bigger, far more deadly and co-ordinated atrocity.
They believe the attacks had been a long time in the planning and orchestrated by a terror cell that worked out of a house containing a large amount of explosives.
Police have linked the two attacks to a terror network of at least eight people based out of a house two hours from Barcelona in Alcanar - a likely bomb-making lab which the bomb-makers accidentally blew up.
Josep Lluis Trapero, police chief in Spain's northeastern region of Catalonia, said he could not confirm the driver of the van that ploughed into crowds in Barcelona, killing 13 people, is dead.
The driver abandoned the van and fled on Thursday after speeding along a section of Las Ramblas, the most famous boulevard in Barcelona, leaving a trail of dead and injured among the crowds of tourists and local residents thronging the street.
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It was the latest of a string of attacks across Europe in the past 13 months in which militants have used vehicles as weapons - a crude but deadly tactic that is near-impossible to prevent and has now killed nearly 130 people in France, Germany, Britain, Sweden and Spain.
Suspected jihadists have been behind the previous attacks. Islamic State said the perpetrators of the latest one had been responding to its call to target countries involved in a US-led coalition against the Sunni militant group.
Hours after the van rampage, police shot dead five people in the Catalan resort of Cambrils, 120 km down the coast from Barcelona, after they drove their car at pedestrians and police officers.
The five assailants had an axe and knives in their car and wore fake explosive belts, police said. A single police officer shot four of the men, Mr Trapero said.
A Spanish woman was killed in the Cambrils incident, while several other civilians and a police officer were injured.
Mr Trapero had earlier said the investigation was focusing on a house in Alcanar, southwest of Barcelona, which was razed by an explosion shortly before midnight on Wednesday.
Police believe the house was being used to plan one or several large-scale attacks in Barcelona, possibly using a large number of butane gas canisters stored there.
However, the apparently accidental explosion at the house forced the conspirators to scale down their plans and to hurriedly carry out more "rudimentary" attacks, Mr Trapero said.
Reuters / Newshub.