- In the first incident the driver of a white van sped into a street packed full of tourists in central Barcelona.
- Some eight hours later in Cambrils, a city 120 kilometres south of Barcelona, an Audi A3 car hit pedestrians, injuring six civilians.
- Police shot dead four of the Cambrils attackers and a fifth later died of his injuries.
Drivers ploughed into pedestrians in two quick-succession, separate attacks in Barcelona and another popular Spanish seaside city Thursday and Friday, killing 13 people and injuring more than 100 others.
In the first incident which police qualified as a "terrorist attack," the driver of a white van sped into a street packed full of tourists in central Barcelona on Thursday afternoon, knocking people out of the way and leaving 13 dead.
Some eight hours later in Cambrils, a city 120 kilometres south of Barcelona, an Audi A3 car hit pedestrians, injuring six civilians — one of them in a critical condition — and one police officer, said the government of the Spanish region of Catalonia where both cities are located.
Police shot dead four of the Cambrils attackers and a fifth later died of his injuries.
They said they were "working on the hypothesis that the terrorists shot dead in Cambrils are linked to what happened in Barcelona".
While little more was known about the attack in Cambrils in the early hours of Friday morning, witnesses in Barcelona told of scenes of chaos and horror.
They recounted how bodies were strewn along the famous Las Ramblas boulevard where the driver went on a rampage as other people fled for their lives, screaming in panic.
The carnage in a city hugely popular with tourists from around the world is the latest in a wave of attacks in Europe where vehicles have been used as weapons of terror.
As world leaders united in condemning the carnage, the IS propaganda agency Amaq claimed that it was carried out by "soldiers" from the jihadist group.
Police announced the arrest of two suspects, identified as a Spaniard and a Moroccan, but said the driver was still on the run.
"We're united in grief," Spanish Prime Minister Mariano Rajoy said in a televised address after rushing to Barcelona, the biggest city in Catalonia, a region in Spain's northeast whose separatist government is defying Madrid with a drive for independence.
"Above all we're united in the firm intention to defeat those who want to take our values and way of life from us."
There were at least 18 nationalities among the Barcelona victims who came from countries as varied as France, Venezuela, Australia, Ireland, Peru, Algeria and China, according to Spain's civil protection agency.
Belgium said one of its citizens had died in the Las Ramblas assault, while The Hague said three Dutch were injured and a Greek diplomat reported three nationals had been wounded — a woman and her two children.
WHOLE STREET STARTED TO RUN