Police have found a total of 120 gas canisters at what they believe was a bomb-making factory operated by the terror cell that attacked Spain this week.

The 12-strong cell were planning to pack the canisters into three rented vans along with plastic explosives in order to carry out a much bigger atrocity, investigators say.

But an accidental explosion on Wednesday killed one member of the cell, may have taken out the group's mastermind, and wounded their suspected bomb-maker, forcing them to switch to 'rudimentary' tactics, officers said.

A total of 120 canisters which contained deadly butane gas were recovered from a home in Alcanar, 60 miles south of Barcelona, which is believed to have been a bomb-making factory operated by the terror cell that attacked Spain

Police say the canisters were going to be packed into three rented vans along with plastic explosives in order to carry out a massive scale attack

But an accidental explosion at the property on Wednesday forced the group to switch to 'rudimentary' attacks which were carried out in the following days before they could be caught

The following day a man believed to be Younes Abouyaaqoubdrove a rented van into crowds in Barcelona, killing 13 and injuring more than 120.

In the early hours of Friday morning five more jihadis launched a car and knife attack in the city of Cambrils, killing one woman and wounding another 10 before being shot dead by a police officer.

While Abouyaaqoub has still not been found, police say the remains of Abdelbaki Es Satty, who is thought to have masterminded the plot, may have been buried in the Alcanar apartment.

Satty is believed to have organised the attacks after radicalising young men through his mosque in the town of Ripoll, where the majority of the attackers lived.

Islamic preacher Abdelbaki Es Satty is thought to have mastermined the attack, and may have been killed in the Alcanar blast

The imam, who was once convicted of smuggling cannabis,has connections with suspects detained over the 2004 al-Qaeda train bombings which killed 191 people and injured 1,500 in Madrid, counter-terrorism sources told El Pais.

News website OK Diario reported the preacher previously lived in Barcelona with members of a terrorist cell which was smashed by police in 2006.

Another of his former flatmates, Belgacem Bellil, blew himself up in a suicide attack in Iraq in 2003, the website said.

Belgacem, an Algerian, detonated 3500lbs of explosives in a truck at a military base, killing 28 people including 19 Italians in al-Nasiriyah in November 2003.

Es Satty also spent two years in prison after being caught smuggling cannabis between north Africa and Spain, El Periodico newspaper reported.

Police are investigating whether Es Satty was responsible for radicalising the members of the cell who carried last week's atrocities in Barcelona and Cambrils.

They searched the imam's flat in Ripoll, Spain, for samples of DNA and fingerprints to verify whether he was killed at the bomb factory where the terror cell prepared a planned attack with butane gas bombs.

Police found the remains of two bodies in the factory in Alcanar and are said to be searching for a third.

Images from inside the home show outdated appliances, white walls and bedrooms with mattresses on the floor.

Papers bearing what appeared to be French names, phone numbers and e-mail addresses were seen by reporters in Es Satty's apartment after it was searched.

The walls are mostly bare, though a couple framed images hang on the walls of the sitting room.

Es Satty, 45, began preaching in Ripoll around two years ago but stopped two months ago, sources at the town's mosque said.

The president of the mosque where Es Satty preached, Ali Yassine, said he hadn't seen him since June, when he announced he was returning to Morocco for three months.

They searched his flat for samples of DNA and fingerprints to verify whether he was killed at the bomb factory where the cell prepared a planned attack with butane gas bombs

Es Satty's flatmate said he hadn't seen him since Tuesday, when Es Satty said he was going to Morocco to see his wife

Images from inside the home show outdated appliances, white walls and bedrooms with mattresses on the floor

The flat's kitchen features patterned wal, paper, a small gas stove and oven, as well as a small refrigerator

The walls are mostly bare, though a couple framed images hang on the walls of the sitting room

In the bathroom, toothbrushes and shaving cream still sit by the sink, next to a large bottle of soap

'He left the same way he came,' said a bitter Wafa Marsi, a friend to many of the attackers, who appeared Saturday alongside their families to denounce terrorism.

Police sources told Spanish media he followed the fundamentalist Salafi branch of Islam.

Detectives were said to be investigating whether he radicalised the young men who planned and carried out the atrocity on Thursday afternoon.

Es Satty's flatmate, named only as Nourddem, said the preacher had left home on Tuesday 'because he was leaving for Morocco'. Nourddem has heard nothing from him since.

'The last time I saw him was Tuesday and he told me that he was going to see his wife in Morocco,' Nourddem told AFP.

Police sources told El Mundo newspaper Es Satty's age and profile suggested he might be the leader of the terror cell. The Mossos d'Esquadra would not comment on that claim.

Everyone so far known in the cell grew up in Ripoll, a town in the Catalan foothills near the French border 100 kilometers (62 miles) north of Barcelona.

A police document published by Spanish media said two alleged members of the group, Youssef Aallaa and Mohamed Hichamy, now both believed dead, had travelled to Zurich in December 2016.

Swiss newspaper Tages-Anzeiger said Swiss police confirmed that at least one of the Barcelona suspects had been in Zurich in December 2016, although it said it was not yet possible to say if the suspects had any connections to Switzerland. An investigation of the visit was under way, it said.

One of the pictures in the flat's living room sits nearly parallel with the door frame, and appears to be an image of a mosque

A bedroom is seen after the police raided the flat where imam Abdelbaki Es Satty lived in Ripoll, north of Barcelona

The entrance to the flat where imam Abdelbaki Es Satty lived is seen after the police raided it

Es Satty, 45, began preaching in Ripoll around two years ago but stopped two months ago, sources at the town's mosque said

The president of the mosque where Es Satty preached, Ali Yassine, said he hadn't seen him since June, when he announced he was returning to Morocco for three months.

Shoes are seen at a mosque where imam Abdelbaki Es Satty preached in Ripoll, north of Barcelona

Police sources told Spanish media Es Satty followed the fundamentalist Salafi branch of Islam

Detectives were said to be investigating whether he radicalised the young men who planned and carried out the atrocity on Thursday afternoon

Spanish police searched nine homes in Ripoll, including Es Satty's, and two buses, and set up a roadblock that checked each car entering the town. Across the Pyrenees, French police carried out extra border checks on people coming in from Spain.

Neighbors, family and even the mayor of Ripoll said they were shocked by news of the alleged involvement of the young men, whom all described as integrated Spanish and Catalan speakers with friends of all backgrounds.

Halima Hychami, the weeping mother of Mohamed Hychami, one of the attackers named by police, said he told her he was leaving on vacation and would return August 25. His younger brother, Omar, slept late Thursday and left mid-afternoon.

Mohamed Hychami is believed among the five attackers shot to death by police in Cambrils. She hasn't heard from Omar since he left.

'We found out by watching TV, same as all of you. They never talked about the imam. They were normal boys. They took care of me, booked my flight when I went on vacation. They all had jobs. They didn't steal. Never had a problem with me or anybody else. I can't understand it,' she said.

Even with Abouyaaquoub at large, Spanish Interior Minister Juan Ignacio Zoido declared the cell 'broken' Saturday.

Families of the local Muslim community gather to denounce terrorism and show their grief in Ripoll, north of Barcelona, Spain

Authorities in Spain and France pressed the search Saturday for the supposed ringleader of an Islamic extremist cell that carried out vehicle attacks in Barcelona and a seaside resort

This rented van brought terror to the streets of Europe when it was driven at speed down a busy street in central Barcelona, killing 14 including a three-year-old boy

A man lying on the street in Barcelona after the van ploughed into pedestrians along Las Ramblas

In addition to the five killed by police, four were in custody and two or three were killed in a house explosion Wednesday. He said there was no new imminent threat of attack.

Police also conducted a series of controlled explosions Saturday in the town of Alcanar, south of Barcelona, where the attacks were planned in house that was destroyed Wednesday by an explosion.

Authorities had initially thought it was a gas accident, but took another look after the attacks.

Initially, only one person was believed killed in the Wednesday blast. But officials said DNA tests were underway to determine if human remains found there Friday were from a second victim. On Sunday, it was revealed that there might be third body.

A police official, speaking on condition of anonymity to discuss the ongoing searches, said investigators believed the remains may belong to Es Satty.

Spanish authorities said on Sunday that they have been unable to identify the remains found in at a house, complicating the manhunt for the Barcelona attackers because they are not confident about who is on the run.

The official said investigators also discovered ingredients of the explosive TATP, used by the Islamic State group in attacks in Paris and Brussels, as well as multiple butane tanks that the group may have wanted to combine with the homemade explosive and load into their vehicles.

A woman cries as she holds a banner reading in Catalan 'we also suffer it' during a demonstration on Barcelona's historic Las Ramblas promenade

A woman holds a banner reading in Spanish 'Islam means Peace' during a demonstration on Barcelona's historic Las Ramblas promenade, where a van attack killed 14 people

People pay their respects at a memorial tribute of flowers, messages and candles to the victims on Barcelona's historic Las Ramblas promenade on the Joan Miro mosaic

A man with his son light candles at a memorial tribute of flowers, messages and candles to the victims on Barcelona's historic Las Ramblas promenade on the Joan Miro mosaic, embedded in the pavement where the van stopped

An official said on Sunday that more than 100 butane gas tanks and explosive ingredients were stored in the house.

Police official Josep Lluis Trapero said 'that makes us think this is the place where they were preparing the explosives'.

He told reporters at a news conference Sunday that the radical cell of 12 people 'had planned one or more attacks with explosives' in Barcelona. The cell rented three vans and also used a car and motorcycle.

Neighbors on Saturday said they had seen three vehicles coming and going from the home, including an Audi used in the Cambrils attack and the van used in the Barcelona attack.

Locals in Ripoll said the preacher had kept to himself and had not integrated into the muslim community in the town. Around 500 north Africans live in Ripoll.

Es Satty gave Arabic classes to children but never revealed any extremist beliefs, locals said. But he did tell people in the town that he travelled regularly to Belgium, a hotbed of Islamic extremism.