Police says suspect Younes Abouyaaquob could have crossed the border into France
The hunt for the man suspected of driving the van in the Barcelona terror crash has been extended to other European countries - as police confirmed there had been a 15th victim of the twin attacks in Spain.
Pau Perez was found stabbed to death in a car which is believed to have been used by one of the attackers as they fled the scene.
As details of the latest developments in the terror investigation were made public, a security alert was issued in the city centre over a suspicious package on a bus, near the main memorial site of the van attack.
It was later confirmed as a false alarm.
Police searching for Moroccan-born suspect Younes Abouyaaquob said he could have crossed the border into France and warned the fugitive was "dangerous and could be armed".
He is dangerous and could be armed. He is sought as the alleged perpetrator of the Barcelona attack on August 17. He was the van driver pic.twitter.com/zKM5kV0RzM— Mossos (@mossos) August 21, 2017
It is believed the 22-year-old was behind the wheel of the white Fiat van that drove into crowds along the Catalan city's famous Las Ramblas boulevard on Thursday.
New CCTV stills emerged on Monday of a man matching his description fleeing the scene on foot.
El Pais newspaper said the images showed the suspect - wearing a striped t-shirt and dark glasses - walking through the nearby La Boqueria market.
Catalan interior minister Joaquim Forn told Catalunya Radio that "everything indicates" Abouyaaqoub, a resident of the northern town of Ripoll, is the only remaining member of a 12-man cell still at large.
The others have either been killed by police or detained.
Abouyaaqoub was pictured on a bank security camera in Ripoll on Wednesday, the day of a bomb factory explosion in Alcanar.
Ripoll is about 320 kilometres away from the scene of the blast in which three people are believed to have been killed and one person injured.
The survivor, Mohamed Chemlal, 20, a suspected bombmaker, is being questioned by police.
Authorities say the house had been rented by the cell to plan a much bigger attack and was full of explosive material, but it blew up accidentally.
As a result, it is believed cell-members resorted to the twin van attacks, first in Barcelona and then in the seaside resort town of Cambrils - where five attackers were killed in a shoot-out with police.
In total, 15 people were killed and at least 120 others injured in the atrocity.
British-born Julian Cadman, seven, who was on holiday with his mother, has been confirmed among the dead. His mother was badly injured and is said to be in hospital in a serious condition.