A woman who was injured in the attack in Cambrils died on Friday bringing the total death toll from both attacks to at least 14.
A woman who was critically injured after a vehicle rammed into pedestrians in Cambrils, Spain has died.
The vehicle attack took place early on Friday about 130 km (80 miles) south of Barcelona eight hours after a van slammed into pedestrians on a busy Barcelona promenade, killing 13 people.
An emergency services spokesman said the number of people injured in a van attack in Barcelona on Thursday afternoon and in Cambrils stood at 130 on Friday,
Seventeen were in a critical condition and another 30 were in a serious condition, the spokesman said.
Emergency services said in a statement that the dead and injured in the two attacks were of 34 different nationalities.
In the seaside resort town of Cambrils, police shot dead five attackers wearing fake bomb belts who were in an Audi A3 that knocked down pedestrians,
The driver of the van in the Barcelona attack is among those shot dead by police.
In all, six people, including a police officer, were injured in the Cambrils attack.
Police said they were "working on the hypothesis that the terrorists shot dead in Cambrils could be linked to what happened in Barcelona."
Earlier on Thursday, a white van jumped the sidewalk in Barcelona's historic Las Ramblas district and rammed into a summer crowd of tourists and residents, police said.
A Turkish national also seriously wounded in Thursday’s terrorist attack in central Barcelona, Turkey's embassy in Madrid confirmed.
Daesh claimed responsibility for the Barcelona attack in a statement released by the militant group's media arm — the Amaq news agency — saying the attack was carried out by their "soldiers."
It said the attack was in response to Daesh calls for its followers to target countries participating in the coalition trying to drive the extremist group from Syria and Iraq.
The statement provided no further details about the attackers.
Four suspects detained
Catalan police say they arrested a fourth person in connection with both the attacks.
Police made the announcement on Twitter.
In a statement released, police said three of the men were Moroccan while the fourth was Spanish.
They are looking for four further suspects linked to the deadly terror attacks, the newspaper La Vanguardia reported.
The suspects, aged 17, 18, 22 and 24, are of Moroccan origin, the online edition of the Barcelona-based newspaper reported citing an internal police document obtained from investigation sources.
Three suspects live in Ripoll, a town of around 10,000 people located about 100 kilometres (60 miles) north of Barcelona, while a fourth is from the Catalan town of Ribes de Freser, the newspaper added.
"We are not afraid"
A crowd in Barcelona's main square defiantly shouted "not afraid" on Friday following a minute's silence attended by Spanish Prime Minister Mariano Rajoy and King Felipe VI, held for the victims of the attacks.
Standing silent in the Plaza de Catalunya, Rajoy joined the king and Carles Puigdemont, the president of the Catalonia region where Barcelona is located, in mourning the victims of attacks that left 13 dead and more than 100 injured.
At loggerheads as the separatist Catalan government attempts to break away from Spain, Rajoy and Puigdemont put their differences aside as they held a minute of silence in the square near the scene of the Barcelona attack.
Crowds thereafter broke out in loud applause, shouting "I'm not afraid."
Vehicle Attacks in Europe
Cars, trucks and vans have been the weapon of choice in multiple extremist attacks in Europe in the last year.
The most deadly was the driver of a tractor-trailer who targeted Bastille Day revelers in the southern French city of Nice in July 2016, killing 86 people. In December 2016, 12 people died after a driver used a hijacked truck to drive into a Christmas market in Berlin.
There have been multiple attacks this year in London, where a man in a rented SUV plowed into pedestrians on Westminster Bridge, killing four people before he ran onto the grounds of Parliament and stabbed an unarmed police officer to death in March.
Four other men drove onto the sidewalk of London Bridge, unleashing a rampage with knives that killed eight people in June. Another man also drove into pedestrians leaving a London mosque later in June.
The deadliest recent attack in Spain was in March 2004, when Islamist militants placed bombs on commuter trains in Madrid, killing 191 people and wounding more than 1,800.