This is reported by the BBC.
The protests erupted a day after Pablo Hasel was jailed for answers insulting the police and the Spanish monarchy.
Thousands of protesters in Madrid and Barcelona clashed with law enforcement. Police said dozens of people were detained, including at least 14 in Madrid and 29 in Barcelona.
In the Spanish capital, the demonstration began peacefully. The protesters clapped their hands and chanted “No more police violence” and ” Freedom for Pablo Hasel”.
But after bottles and rocks were thrown at the commandos, they used tear gas and rubber bullets.
Similar scenes of violence were seen in Barcelona, where protesters set up barricades and set fire to furniture in the streets.
According to the police, they threw stones, bottles, and blunt objects, which forced law enforcement officers to respond with special means.
Violent protests were reported in Lleida, the city where the 32-year-old rapper was born and where he was arrested, as well as in the cities of Girona and Tarragona.
Hasel, whose real name is Pablo Rivadulla Duro, was jailed on Tuesday. Last Friday, he missed a deadline to turn himself into the police and begin serving a prison sentence set for 2018.
Police stormed the university building where Hasel had barricaded himself and arrested him, sparking rallies and riots in Barcelona and other Catalan cities.
The rapper faces nine months in prison for glorifying terrorism and insulting the crown in tweets and lyrics.
The case of Hasel, who is known for his radical left-wing views, has revived the debate about free speech in Spain.