Story highlights Basque separatist attacks have stopped after a five-decade insurgency

Madrid was hit by its deadliest attack in 2004, in which 191 people died

(CNN) Spanish police say they are treating a deadly van ramming in Barcelona as a terror attack -- a revelation that is likely to come as a shock to a country that has largely been spared the assaults that have hit its neighbors in recent years.

The Spanish capital, Madrid, was hit by its deadliest terror attack in history in March 2004, when coordinated bombings on commuter trains killed 191 people and injured 1,800 more.

The bombings were blamed on Islamist militants, who were based in Spain but inspired by al Qaeda.

When that attack happened, Spanish media and officials thought initially that the Euskadi Ta Askatasuna (ETA), a Basque separatist group, might have been responsible.

The Spanish government says that ETA has carried out more than 1,600 attacks and killed more than 800 people in its decades-long fight for an independent Basque state that it wants carved out of sections of northern Spain and southwestern France.

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