Rapper Pablo Acel was accused of glorifying terrorism and insulting the monarchy
Police fired tear gas, rubber bullets, and stun grenades at protests in Madrid and Barcelona, each attended by thousands of people.
The actions followed the arrest of rapper Pablo Acel on charges of glorifying terrorism and insulting the royal family in his songs.
Acel was detained in the Catalan city of Lleida on Tuesday.
The protests in Madrid’s central square were peaceful at first. People clapped their hands and chanted “No to police violence” and “Freedom for Pablo Acel.”
But after several protesters began throwing glass bottles and rocks at police officers, which they plucked from the sidewalk, law enforcement officers burst into the crowd and used batons.
Some demonstrators set garbage cans on fire to erect barricades in Madrid’s narrow streets.
In the Catalan capital, Barcelona, similar events occurred when local police used rubber bullets against the crowd, one of which injured a Reuters journalist who was on the spot.