King Felipe VI and Queen Letizia joined politicians at the Sagrada Familia basilica to honour the 14 people killed and more than 120 wounded in Barcelona and nearby Cambrils. Five attackers wearing fake explosive belts were also shot dead in the Catalan town.
A counterterrorism expert who has been briefed on the investigation, speaking on condition of anonymity, said investigators believed the plot had been in the works for almost a year.
Authorities have yet to identify the driver of the van and his whereabouts are unclear.
The German public broadcaster DW is now reporting the Spanish police is using a robot to approach the body, as they fear they could detonate the bomb.
Police found the suspect hiding in a vineyard.
Scotland Yard reviewed the security of 33 bridges around the British capital, and several were fitted with special vehicle-resistant barriers as a result.
"In the end Muslims are the main victims, for the deaths as well as for the social pressure", said Xantal Genovart, vice president of the Association of Catalan Muslim women.
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.
Complicating the manhunt, though, was the fact that police have so far been unable to officially identify who exactly is at large.
"We are a broken family", niece Raquel Baron Lopez posted on Twitter.
The other eight were killed by security forces or blown up in an explosion believed accidentally detonated in the attackers' bomb factory.
In Britain, guidance for armed police been revised so that firing at a vehicle on the move is accepted for incidents such as those seen in Nice and Westminster. It is unclear if he is dead or alive.
"It is understood that they planned one or more terrorist attacks in Barcelona", Trapero said.
Details of the victims of twin terror attacks in Spain are slowly emerging, with an American, three Italians and a Canadian among those named who were killed.
Tennis ace Rafael Nadal was "shattered" by the news.
"My children go to school here and I don't want people to look at them negatively because of some barbarians", said Rouj, who moved to Spain from Nador in northern Morocco when he was just 16.
Although much attention in the Spanish media has been paid to the Moroccan origins of the terrorists, Puigdemont was careful to defend the role of the minority group, numbering around 200,000, in the region.
Abouyaaqoub lived in Ripoll, a town north of Barcelona close to French border.
A minute's silence was then observed, a mark of respect that was also made at other matches across Spain over the weekend. The fact he could be assisted gave her hope.
Inside, a mix of locals and tourists fill the pews, many snapping photographs of the cathedral's vaulted ceilings and stained glass windows on their cellphones.
Spain is the world's third tourism destination and does not want to scare visitors away as it depends on the sector for its recovering economy. However, he said, he believed the connection to the Islamic State was real. Spanish media outlets reported that while the authorities believe that Abouyaaqoub was the driver of the van, they cannot prove this suspicion at the moment. "He finished his sentence and went free".
Nodir claims he has heard nothing from him since.
"We found out by watching TV, same as all of you".
"It will never be the same".