Here we go again.
Summary
Officials say 13 killed and at least 50 injured when van crashes into crowd
Police say the incident is being treated as a terrorist attack
One person has been arrested, but it's not clear if it is the driver
People took cover in nearby shops and cafes
The famous Las Ramblas boulevard is a tourist hotspot
Police release picture of suspect
Police in Barcelona have released a picture of the man who allegedly rented the van used in the attack.
Driss Oukabir, in his 20s, was born in Morocco, according to local media.