Yesterday's attack was so horrible.
Four men have also been arrested in connection with the attacks - three Moroccans and a citizen from Spain's North African enclave of Melilla.
Spanish police have also tipped off their French counterparts about a white van linked to the attacks that may have crossed the border, a French police source told AFP.
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.
Police suspect the property was being used as a base to make explosives that could have been used in even more devastating attacks in Barcelona, Cambrils and possibly elsewhere, had they not blown up prematurely.
Police said they believe these incidents, including an abandoned vehicle that was recovered, are all connected to the same group of people.
As of Saturday morning, 54 injured people are still hospitalized with 12 of them in critical condition, according to Catalan emergency services.
Police in Catalonia said they were searching for Abouyaaqoub, living in the Spanish town of Ripoll.
In addition to the five people killed in Cambrils, police said they arrested two people Friday, after the two arrests a day earlier. "Many people were killed and many more were injured". It took a very short time for ISIS to claim responsibility for the attack.
- One person was killed and seven others were injured.
But details of their alleged roles, the identity of the driver of the van and the number of attackers involved remain unclear.
Around 4:50 pm (1450 GMT) on Thursday, a vehicle ploughed into a crowd of pedestrians on the famous Las Ramblas boulevard in Barcelona.
The five attackers died from a shootout with police.
"The second attack appeared to be precipitated by the first.
And it really affects you, when it happens in Barcelona and it is the work of people from Ripoll". But then he maneuvered left and accelerated full speed down the Ramblas and I realized it was a terrorist attack.
His sons had shown no sign of radicalisation, he added at his home in Melouiya, a village high in Morocco's Atlas Mountains.
"It all depends on how well he was prepared for this". He decided not to publish the image widely until four years after the attacks. "They got out of the car, they stabbed another pedestrian".
The three have been identified as Moussa Oukabir, 17, Said Aallaa, 18, and Mohamed Hychami, 24.