Dozens of people were taken to hospital after Police and student demonstrators clashed at the Plaza de Cataluna square in Barcelona.
The protests, which have been going on for two weeks, took a sudden turn for the worse after city cleaning crews were sent in to clear away a camp.
Chants of ‘No Violence’ were heard from the crowds and many protesters sat on the ground to further complicate the clean up in a show of pacifist unity.
Some reports say Catalan Police fired rubber bullets and used trunchens to disperse the demonstrators.
The protests are part of an ongoing social movement across Spain against mainstream political parties, soaring unemployment, corruption and welfare cuts.
Police have cleared the encampment because the square is expected to be besieged by football fans during the Champions league Final between Barcelona and Manchester United at Wembley.
The Activists have vowed to return on Sunday to decide how to carry on the movement.