One of the alleged Barcelona plotters has admitted a bigger attack was planned, judicial sources say.
Mohamed Houli Chemlal was testifying in the Madrid high court, where the four surviving suspects are appearing.
He was injured in an accidental blast that reduced a house to rubble in the town of Alcanar last Wednesday.
Assailants went on to kill 15 people and injure more than 100 in a series of attacks in and around Barcelona the following day and early on Friday.
Eight members of the alleged cell are dead – two were killed in the Alcanar explosion, and six were later shot by police.
The last suspect to be killed was Moroccan-born Younes Abouyaaqoub, 22, believed to be the driver of a van which tore down Barcelona’s Las Ramblas boulevard, leaving 13 people dead.
Wearing a fake explosives belt and armed with knives, he was shot dead by police in a vineyard west of Barcelona on Monday.
The surviving suspects were moved, under high security, from Barcelona to Madrid for Tuesday’s hearing.
Judicial sources say he admitted a bigger attack using explosives had been planned. Spain’s El Mundo newspaper reports Houli Chemlal telling the court the iconic Sagrada Familia cathedral was one of several targets.
Investigating judge Fernando Andreu was expected to read out the charges including terrorism, murder and possession of arms.
Houli Chemlal was the first to testify, wearing hospital pyjamas. He is still being treated for his injuries from the blast in Alcanar.
A cache of 120 gas canisters was found at the destroyed Alcanar house and the blast is believed to have prompted the plotters to change the nature of the attack.
Two other suspects were killed in the explosion, including Abdelbaki Es Satty, the Moroccan imam from the town of Ripoll thought to have been a radicalising influence on the suspects.
Five suspects were shot dead as they drove a car at pedestrians in the resort town of Cambril only hours after the Barcelona attack. A Spanish woman was killed in the Cambrils attack.
A Spanish man was stabbed to death soon after the Las Ramblas van attack when Abouyaaqoub escaped on foot and commandeered his vehicle.
The other suspects in court are:
– 28-year-old Driss Oukabir: he has already protested his innocence. His passport was found in the Las Ramblas van but he says his brother Moussa – killed after the attack in Cambrils – had stolen his documents
– Mohammed Aallaa, 27, alleged owner of the Audi car used in the Cambrils attack
– Salah al-Karib, 34, accused of running an internet cafe in Ripoll used to send money to Morocco.
The judge will decide whether to remand the suspects in custody and deny bail as demanded by the prosecutor.
As Tuesday’s Madrid hearing took place, Cambrils victim Ana Suárez, who was in her 60s, was buried in a private ceremony in Zaragoza.
Forty-five companies in a Catalonia association of undertakers and funeral companies have offered to perform funerals for the victims without charge.
Meanwhile, French Interior Minister Gerard Collomb has confirmed previous reports that some of the attackers made an overnight visit to France days before.
He told BFMTV it had been an “extremely fast return trip” to the Essonne area of Paris on 11-12 August, during which their Audi A3 had been caught on speed cameras.
But he insisted the cell had no French links – “they were exclusively Spanish”.
Most of the 12 suspects lived in Ripoll, north of Barcelona close to the French border. All were young men of North African descent.