A second person has been arrested in the Spanish town of Ripoll in connection with the Barcelona terror attack that killed 13 people, bringing the total detained to three.
Joaquim Forn, a Catalan councillor with responsibility for the interior, said: "Another person has just been detained in Ripoll who could be implicated.
"That makes two arrests in Ripoll and a third in Alcanar."
Catalunya's regional president, Carles Puigdemont, said at least one more potential terrorist was still being hunted.
It comes after the arrest of Driss Oukabir, a resident of the town which lies about 60 miles north of Barcelona, in connection with the attack in Barcelona's busy La Rambla promenade.
Mr Oukabir, 28, a French citizen of Moroccan descent, presented voluntarily to police in Ripoll and claimed his younger brother Moussa had stolen his identity documents.
Some 100 people were injured in Thursday afternoon's attack, including more than a dozen with serious wounds. Authorities say the death toll may rise due to the severity of some people's injuries.
Isis claimed responsibility for the massacre, which followed the pattern of numerous others in recent months that used vehicles to target pedestrians. The van driver fled after mowing down his victims, and witnesses said he did not appear to be armed.
"All of a sudden there was an immediate stampede and police shouting at people to run," one told The Independent.
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La Rambla is a wide, tree-lined boulevard and is home to dozens of shops, restaurants and bars. It is popular with tourists and would have been packed in the early evening.
The central part of the street is a tiled pedestrian promenade through which the terrorist's van was driven.
Ethan Spibey, 25, told The Independent: "People were running into shops and taking refuge in cafes. There was a lot of screaming.
"People just turned and sprinted in the opposite direction as the police were screaming at people to run away. They were telling people to get away as soon as possible. It was very scary."
People from 24 countries were among the dead and injured, including 26 French nationals.
In a second incident in the town of Cambrils during the early hours of Friday, police shot dead five people to end another attack using the same method as the first.
A gang wearing suicide belts rammed civilians with a car before being brought down, leaving seven people, including a police officer, injured.
The suicide belts were later revealed to have been fake, in an echo of the London Bridge attack earlier this year.
Police are linking the two incidents, as well as a house explosion in Alcanar on Wednesday that left one person dead. A cell of eight people may have been involved in a plot using gas canisters, authorities announced on Friday morning.
The La Rambla massacre is the deadliest terror attack in Spain since more than 190 people were killed in the 2004 Madrid train bombings.
King Felipe and Prime Minister Mariano Rajoy are due to attend a vigil in Plaça Catalunya at 12pm local time.
Barcelona's city leadership will meet an hour earlier in an extraordinary session, La Vanguardia reported.
Catalan police, the Mossos d'Esquadra, have warned people walking in the area of Plaça Catalunya not to wear backpacks or carry large bags.
UK diplomatic staff in Spain are "in contact with local authorities and urgently seeking further information" following the attacks, the Foreign and Commonwealth Office said.
It added: "If you’re caught up in an ongoing incident, turn any mobile phones or other devices to silent, and do not put your location on social media. Follow the advice of the local authorities when instructed."
