Police clashed with Antifa protesters who had taken to Barcelona streets to counter a demo by Vox party supporters on Saturday.
Antifa protesters removed security fences separating the t demo and its counter-rally, threw stones at the police and set dumpsters and wood on fire in the Catalan capital.
According to reports, seven people were arrested in the unrest and five suffered minor injuries.
Vox is against regional autonomy in Spain and sued both the Parliament of Catalonia and several individual pro-independence politicians following the Catalan independence declaration.