The authorities in Alcanar carried out controlled explosions Saturday morning — “If you hear detonations DO NOT be alarmed,” the Catalan police said on Twitter — because of concerns that there might still be more explosives and gas canisters in the rubble.

Image Younes Abouyaaqoub Credit... Catalonian Police, via Agence France-Presse — Getty Images

So far, seven people believed to be part of the cell have been killed, and four have been arrested. But with at least one more suspect still unaccounted for, Spaniards remained on edge, even though the authorities said on Saturday that the cell had been broken up and that there was no imminent threat of another attack.

The Spanish and Catalan authorities decided on Saturday to maintain the terrorist threat level at 4 (on a scale of 5), but said that security would be reinforced. The Islamic State militant group, which quickly claimed responsibility for the attack in Barcelona on Thursday, said that it had been behind the deadly events in Cambrils, as well.

While officials agreed on the threat level, there appeared to be some disagreement about the status of the investigation. Spain’s interior minister, Juan Ignacio Zoido, announced that the terrorist cell had been dismantled, but his regional Catalan counterpart, Joaquim Forn, told reporters later on Saturday that “we can’t say the investigation is finished until we locate or detain all those who we think form part of this terror cell.”

The cell, Mr. Forn added, cannot be described as “absolutely dismantled.”

The focus of the manhunt on Saturday was Younes Abouyaaqoub, who is believed to have fled on foot after weaving a van through Las Ramblas, a central pedestrian area of Barcelona.

There was no indication that Mr. Abouyaaqoub or the other young men, ages 17 to 34, who were believed to be part of the cell had any connection to extremist or terrorism-related activities.

The counterterrorism expert said that investigators were looking into the possibility that the suspects had lived double lives, noting that some of their Facebook pages demonstrated an interest in clubbing, girls, selfies and hair gel.