About 2,000 people attended the protest, dubbed the "Siege of the Congress" Thursday outside government headquarters in Madrid, ThinkSpain reported.
The event started out peacefully but protesters started throwing objects at police officers, authorities said.
Thirteen police officers were among the injured, the report said.
At least 1,400 riot police officers were dispatched to the scene to disperse the crowd.
Notable deaths of 2014 [PHOTOS]