Catalan police were warned two months ago about a possible terrorist attack on Las Ramblas, Spanish media have reported.
The CIA told Los Mossos, the Catalonian regional police force, that Barcelona was a top target for jihadist terrorists as recently as June this year, El Peridoco, a local paper, reported on Friday.
“Two months ago the Central Intelligence Agency passed a notice to the Catalan autonomous police,” the paper said. “It even warned of the risk to Las Ramblas,” the pedestrian thoroughfare hit by an attack on Thursday.
The Telegraph could not immediately verify the report.
The reported warning followed a series of high-profile vehicle attacks in London, Stockholm, Berlin, and Nice and came amid a mounting concern amongst Spanish and foreign intelligence agencies that the Catalan capital could be next on the jihadist hit list.
The last successful Islamist terrorist attack in Spain was in March 11 2004, when a suspected al Qaeda terror cell exploded bombs on several Madrid commuter trains in a series of coordinated attacks, killing 192 and injuring more than 2,000.
Spanish and foreign intelligence agencies have long seen Catalonia as a high-risk area.
In 2007 the US Embassy in Madrid proposed setting up an intelligence hub in Barcelona to counter a “major Mediterranean centre of radical Islamist activity.”
Eduardo Aguirre, the-then US ambassador in Madrid, said in a cable published by Wikileaks in 2010 that heavy immigration from North Africa and Asia had made the region “a magnet for terrorist recruiters” but that Spanish authorities had little capability to penetrate potential terror cells there.
In October last year Catalan police stepped up security at the Sagrada Familia, the iconic unfinished cathedral designed by Antoni Gaudi, after an Isil-linked publication included it in an image of four key terror targets around the world.
The others the Colosseum in Rome, the Statue of Liberty in New York, and Big Ben in Westminster, where five people were killed and 49 injured in a vehicle attack in March.
According to the Spanish interior ministry, more than 180 “jihadist terrorists” have been arrested since June 2015, when Spain raised the terror alert level to four out of a maximum of five.
Spanish police and intelligence services assigned an extra 3,000 officers to investigate potential threats across the country.
More than 150 combatants from Spain have travelled to Syria to fight with Isil and the whereabouts of many of those remains unknown.
Police believe the high concentration of Western tourists who flock to Spain and the fact it was once under Muslim rule also make it an attractive target for jihadist terror.