Cafe chairs were thrown during scuffles between supporters of Pro-Spanish unity and Pro-Catalan independence in Barcelona.

The incident, involving several people, took place on the fringes of a demonstration in support of Spanish unity at the nearby Pla├ža de Catalunya.

Tension remains high between the central government and Catalonia after the region’s leader signed a symbolic declaration of independence on Tuesday, citing the results of an October 1 referendum which had been declared illegal by Madrid.

The wealthy region’s intention to break away has plunged Spain into its worst political crisis.