Carles Puigdemont, president of the region of Catalonia where both cities are located, warned the suspect still on the run was potentially dangerous, saying "these types of people have already demonstrated they have the will to harm whatever happens".
"We were on the city tour bus, we were 20 feet [6m] from the accident when it happened", said Alex Luque, a 19-year-old student from New York."We heard the van and the impact with people and then we saw people running".
"Our hypothesis is that an attack was being prepared for some time from this Alcanar house", he added.
The Oukabir brothers are of Moroccan heritage but now live in Spain: Driss in Ripoli and Moussa in Barcelona. According to police, the terrorist group had used the house as a place to hide and manufacture weapons.
The five men attempted to drive into tourists on the Cambrils seafront, police said. The vehicular assaults were deadly, but the bomb attack could have potentially been far more damaging.
Spain's Interior Minister Juan Ignacio Zoido has confirmed that the terror cell responsible for the attacks in Barcelona has been dismantled and all its members have been arrested. One of them was Spanish while three of the captured suspects were citizens of Morocco.
However, the apparently accidental explosion at the house forced the conspirators to scale down their plans and to hurriedly carry out more "rudimentary" attacks, Trapero said.
Hours after the Barcelona carnage, a similar attack struck in the seaside town of Cambrils early Friday.
They lay on the ground, without knowing what was going on, before they were eventually allowed to leave and walked back to their hostel. His mother was reportedly among the seriously injured.
London [U.K.], August 19:A manhunt is underway across Europe to find the main suspect, the driver of the white Renault Kangoo van that was involved in the terror attack on Las Ramblas in the heart of Barcelona, amid fears that he may have crossed into France.
In a statement to the station via a family spokesperson, Nunes said she "asks that the community and media hold their family up in prayer and asks for the privacy during this difficult time".
On Thursday, a van ran over pedestrians on Barcelona's Las Ramblas strip.