At least 13 people have died and 50 were injured 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 – had fled on foot.
But police denied earlier reports of two suspected attackers being holed up in a bar in the city centre.

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.
Meanwhile police released a photo of a man named as Driss Oubakir, who is alleged to have rented the van used to drive into pedestrians.
Local media say he is in his 20s, and was born in Morocco.
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.