Barcelona attack: Suicide vest found in exploded safehouse in Alcanar, say Catalan police

Around 100 butane canisters and a type of explosive often used by Isis were also found within the rubble

The house in Alcanar where police say they found a viable suicide belt (EPA/JAUME SELLART)

A suicide belt has been found in the house used to plan a terrorist attack in Barcelona, Spanish police have said.

It is believed the property in the town of Alcanar, a coastal town about 200 kilometres (124 miles) south of Barcelona, was used as a bomb factory by the cell responsible for two vehicle ramming attacks and a carjacking last week. Combined, the violence left 15 people dead and 120 injured.

The house in Alcanar was destroyed in a suspected gas explosion the night before the attack after bomb-making preparations went wrong, police believe. The alleged ringleader, imam Abdelbaki Es Satty, 45, died in the blast.

Another suspect also died in the explosion, which investigators initially thought was linked to a drug laboratory.

At least 100 butane gas canisters were found in the remains of the destroyed property. In addition, investigators found traces of triacetone triperoxide, the same explosive used in the Manchester attack and often used by Isis.

The extremist group claimed reasonability for the attacks and released a propaganda video praising their actions. It is the first time an Isis video has featured Spanish-speaking fighters, according to security analyst Rita Katz.

Mohamed Houli Chemlal, 21, survived the Alcanar explosion and was arrested. He admitted in court on Tuesday that a larger attack was planned before the militants’ plot went wrong.

Six attackers wearing fake suicide vests, including the suspected van driver Younes Abouyaaqoub, were shot dead by police.

But authorities fear the attacks could have been far more devastating if explosives had been used, potentially with the hired vans to create Vehicle Born Improvised Explosive Devices (VBIED).

The death toll could have reached the hundreds if the terrorists’ suspected original plans had been carried out in full, officers said.

Among the Barcelona landmarks the terrorists intended to target was the Sagrada Familia basilica, popular with tourists from around the world.

Chemlal and another suspect, Driss Oukabir, have been charged with murder, possession of explosives and membership of a terrorist organisation. Another, Salah el Karib, is being held while officers continue their enquiries. And a fourth man, Mohammed Aalla, has been freed on bail due to a lack of evidence.

The investigation has been continuing in earnest in Spain, where two police raids took place late on Tuesday night.

Officers said they were investigating objects recovered in a cybercafe in Ripoll, where a suspect now in custody worked, and a house in Vilafranca del Penedes.

Vilafranca is close to where Abouyaaqoub was shot dead on Monday. He is known to have changed clothes, picked up knives and a fake explosive belt in the time between the attack on Thursday and his death. Investigators are trying to establish where he spent four days in between.

But no details were given on the nature of the material found during the searches.

Questions have also been raised about the communication within Mossos d'Esquadra following the Alcanar blasts. Sources told Reuters the terrorists’ plans could have been discovered sooner had specialist bomb squad officers been sent immediately to the levelled house.

And the Times reported Belgian police warned the Catalan authorities Es Satty, a convicted drug smuggler, was suspicious last year but were told by the Spanish he had no terror links.

The investigation has also branched into France, where a group of the suspects visited Paris briefly just two days prior to the attack. An Audi used by the attackers to ram pedestrians in Cambrils was caught by a speeding camera outside the French capital.

Spain's interior minister, Juan Ignacio Zoido, visited his counterpart the neighbouring country on Wednesday.

"We are working to determine why the authors of the attacks came to Paris and what they did in the Paris region," said Gerard Collomb, the French minister.

Dozens of French nationals were hurt in last week’s attack.

France has experienced a number of significant Islamist terrorist attacks in recent years, which have left 238 people dead since January 2015.

Additional reporting by agencies.