Spanish police shoot dead five terrorists 'wearing explosive belts' in second attack

Five men "wearing explosive belts" have been shot dead by police in a second Spanish terrorist attack, just hours after a van ploughed through crowds in Barcelona killing 16.

Witnesses are believed to have called emergency services after hearing gunfire in the town of Cambrils, 100 kilometres south of Barcelona in Spain, just after midnight on Thursday.

Just eight hours earlier, more than 100 were injured after a van ploughed through crowds in Las Ramblas, Barcelona, in a shocking terror attack.

Police confirmed the two incidents were linked and told locals to "stay home and stay safe." Six civilians and a police officer were injured in the Cambrils operation.

Video taken by a witness shows a number of police vehicles with flashing sirens in the distance.

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A number of gunshots can be heard and bystanders can be seen running and hiding behind a nearby bicycle stand.

This comes just hours after a van ploughed through crowds in Las Ramblas, leaving a trail of carnage and more than a dozen dead.

Before the van ploughed into the tree-lined walkway of Las Ramblas, one person was killed in a house explosion in a separate town southwest of Barcelona. Residents there were preparing explosives, a police source added.

Suspect Driss Oukabir, 28, was arrested by police and is believed to have rented the white Fiat van used in the attack on the pedestrians.

Shortly after, Islamic State said its "soldiers" were responsible for carrying out the killing.