Spanish police hunting for the driver of the van used in the Barcelona attack are focusing their efforts on a 22-year-old Moroccan national, according to reports.
Younes Abouyaaqoub is said to be at the centre of the investigation into the massacre on Las Ramblas that left 13 dead and nearly 130 injured.
According to Spanish newspaper El Pais, police in Catalonia said they were searching for the man, who is understood to be a key member of a 12-strong jihadist cell responsible for the attacks.
On Friday it emerged that another suspect Moussa Oukabir, who is thought to have rented the van, was among five men shot dead as they launched a second attack in the coastal town of Cambrils.
The teenager, said to be 17 or 18 years old, is suspected of using his brother's documents to hire the vehicle that ploughed through pedestrians in the tourist hotspot on Thursday evening.
He reportedly died along with Said Aallaa, 19, and Mohamed Hychami, 24, who were part of a group that mounted a similar attack in Cambrils that left one woman dead and six people injured.
The identities of the other two dead jihadists are yet to be confirmed by police.
Four men, aged 21, 27, 28 and 34, who were arrested in connection with the attack remain in custody.
Three are Moroccan and one Spanish, and police said none of them was previously known to the security services for terror-related reasons.
Moussa Oukabir's older brother, Driss Oukabir, is reported to be one of those detained.
Some 34 nationalities were among almost 130 people wounded in the attacks in Las Ramblas and in Cambrils, which lies around 70 miles to the south west.
Local authorities have identified six of the victims of the Barcelona attack as an Italian, one Portuguese, three Spanish and one Spanish-Argentine.
The victim of the second assault in Cambrils has been identified as a Spanish woman.
Relatives of a seven-year-old who became separated from his mother during the Barcelona attack are continuing to appeal for information.
The father and grandmother of Julian Alessandro Cadman are travelling to Spain from Australia as the wait for news continues, family member Debbie Cadman said.
Speaking after the family's initial plea for help, Prime Minister Theresa May said a child with dual British nationality was believed to be among those unaccounted for.
Australian prime minister Malcolm Turnbull urged his compatriots to pray for the youngster.
"There's a little Australian boy whose mother was badly injured and he is lost, he's missing in Barcelona," Mr Turnbull said.
Four Australians were injured in the attack, the country's foreign minister, Julie Bishop, said.
Canada's prime minister Justin Trudeau said one Canadian was killed and four injured during the attacks.
He said: "We join Spain and countries around the world in grieving the senseless loss of so many innocent people.
"We must stand firm against the spread of hate and intolerance in all its forms. These violent acts that seek to divide us will only strengthen our resolve."
Vancouver Police Department confirmed the Canadian killed in the attack was Ian Moore Wilson.
A statement released by his daughter Fiona, a staff sergeant in the force, said he was a "much-loved husband, father, brother, and grandfather" and was compassionate, adventurous and generous.
"In the midst of this tragedy, my dad would want those around him to focus on the extraordinary acts of human kindness that our family has experienced over the past several days, and that is exactly what we intend to do," the daughter said.
Authorities said 54 people injured in the attacks were still in hospital on Saturday, with 12 in a critical condition and 25 in a serious condition.
It comes after police revealed the terrorists behind the rampage were preparing bigger attacks, with a suspected gas explosion on Wednesday at a house in Alcanar believed to have robbed the killers of materials to use in larger-scale operations.
Reports from Spain had earlier suggested the terror cell may have been planning an attack using gas canisters.
Catalan regional police official Josep Lluis Trapero told reporters on Friday: "We think they were preparing at least one or more attacks in Barcelona.
"The explosion in Alcanar at least avoided some of the material they were counting on to carry out even bigger attacks than the ones that happened.
"Because of that the attack in Barcelona and the one in Cambrils were carried out in a bit more rudimentary way than the one they had initially planned."
Police are also looking for a white Kangoo vehicle which is believed to have been rented by the suspects and could have crossed the border into France, according to French media.
The attacks in Barcelona and Cambrils took place around eight hours apart on Thursday afternoon and in the early hours of Friday.
In an echo of the London Bridge attack in June, Catalonia president Carles Puigdemont said the five terrorists in the Cambrils car were wearing fake suicide belts when they were stopped.
Police revealed that an axe and knives were also found in the vehicle, with one of the latter used to wound one person in the face before the terrorists were gunned down.
Barcelona came to a halt at noon on Friday as a minute's silence was observed in the Placa Catalunya, close to the scene of the attack, followed by applause for the victims.
Meanwhile police in Finland have said a stabbing in the city of Turku, 90 miles west of the capital, Helsinki on Friday is being investigated as murder with possible terrorist intent.
With two people killed in the attack, police said the suspect who was shot by officers and arrested, is an 18-year-old Moroccan citizen whose identity is known to them.