Barcelona car attack
© AP Photo/ Manu Fernandez
According to police, some 120 gas canisters found for "one or more" attacks in the Spanish city of Barcelona in the region of Catalonia.

According to the Catalan police chief, Thursday's attack hasn't been "committed on the full scale" because explosives had been destroyed as a result of an accidental blast in Alcanar a day before the terror attacks.

"We're starting to see clearly that (the Alcanar house) was the place where they were preparing explosives for one or more attacks in the city of Barcelona," Josep Lluis Trapero, chief of Catalonia's police force (Mossos d'Esquadra) said.

Catalan police also said that the ramming attack in Barcelona was conducted by one person. Police still don't know if the attack perpetrator is still at large. He may have crossed the Spanish border with France. The police added that the increased measures of control were still in place in Catalonia, especially on the border with France.

"We think that one person committed this crime," Trapero said at a press conference, broadcast on the El Pais newspaper's website.

"Investigation goes on and we keep on working. We are looking for a person related to the attack, but we can't confirm degree of [his] authorship," the police wrote on Twitter.

The official confirmed that four terrorists out of 12 suspects in the attack have been arrested and five others were killed. The identities of three suspects were established. Two or three more attackers allegedly died in an explosion in the Catalan town of Alcanar a day before the ramming attack, while one suspect remains at large.

The police chief confirmed that a terrorist cell behind the attacks has been eliminated.

On Thursday, a van plowed into a crowd of pedestrians on Las Ramblas street in Barcelona, killing 14 people and injuring more than 100 others, in what police said was an act of terrorism.

Hours after the incident, another vehicle attack took place in the coastal town of Cambrils, south of Barcelona, killing one and injuring five civilians as well as a police officer. Daesh terrorist group claimed responsibility for the attacks.

On Saturday, the Spanish Interior Ministry said that a terror cell has probably been behind the Barcelona attack.