A special mass to remember the victims of the Catalonia terror attacks is taking place at the famous Sagrada Família Basilica in Barcelona.

Members of the Spanish royal family are among those honouring the 14 people killed and 130 injured in Thursday's incident.

It comes after Spanish police raided the home of an imam who they believe may have radicalised the Barcelona and Cambrils attackers.

It is reported that Abdelbaki es Satty is the ringleader of the terror cell and was responsible for directing the terrorists to commit the attacks in Spain which killed 14 people.

Spanish officials are to boost security at crowded areas and sites popular with tourists following two attacks in the country.

There are 53 people still in hospital, 13 of them in a critical condition, while another 78 people have been released after treatment.

Spain's interior minister Juan Ignacio Zoido confirmed increased security for events that draw large crowds as well as at popular tourist sites.

Spanish media also said that security at the border with France was being strengthened, while French police carried out extra border checks on people arriving from Spain.

There will be extra security at Barcelona's Camp Nou stadium today, with nearly 100,000 people expected for the team's first game of the season against Real Betis.

The game will include a minute of silence for the victims and Barcelona's football team will wear black armbands and special shirts, bearing the Catalan words for "We are all Barcelona."

Catalan regional police are mounting road blocks in the northeast of Spain as officers search for at least one man suspected to have been involved in the Barcelona attack, who is still on the run.

Younes Abouyaaqoub, 22, is a Moroccan national who was living in the Spanish town of Ripoll, where his flat is one of nine addresses raided by police on Saturday.

He is not believed to be among those held or shot dead by police in the coastal resort of Cambrils, where the second attack took place.

King Felipe and Queen Letizia visit the terrorist attack victims at the Hospital in Barcelona, Spain, 19-08-217. Image: Archie Andrews/ABACAPRESS

Earlier, Spain's King Felipe and Queen Letizia visited the site of the attack at Las Ramblas, placing a wreath and two candles on the ground.

They were accompanied by Catalan regional president Carles Puigdemont and Barcelona Mayor Ada Colau.

Earlier, the royal couple visited a hospital where many victims from Thursday's attack were being treated, also speaking with medical staff.

Catalan emergency services have said that seven of the 14 victims have been identified from both attacks, including four Spaniards, two Portuguese and an Italian, while family members or government officials have said a US man, a second Italian and a woman from Belgium were also killed.

Spanish authorities have also said that the terror cell behind deadly twin attacks has been "dismantled."

In a news conference, interior minister Mr Zoido said the cell comprised 12 young men, many of them Moroccan, and some teenagers.

"The cell has been completely dismantled," he told reporters.

With reporting from IRN ...