At least 13 person died and 100 were injured -of them seriously – after a van ploughed into crowds in Barcelona’s famous Las Ramblas tourist area, police and local officials say.
The vehicle sped along the pedestrian area, mowing down people and sending others fleeing for cover. Police are treating the incident as terrorism.
Later they said a man had been arrested in connection with the attack.
Witnesses said the van had deliberately targeted people before stopping.
Spanish media reports said the driver of the vehicle – a white Fiat that had been rented in the city – fled on foot.
Other unconfirmed reports say the death toll is as high as 13.
Local authorities in the small town of Vic in Catalonia say police have cordoned off the area and are inspecting another van amid suggestions it may have been used as a getaway vehicle.
The attack happened at the height of the season in one of Europe’s top tourist destinations.
Vehicles have been used to ram into crowds in a series of attacks across Europe since July last year.