The protests in Barcelona have been going on for a week.
But there are reports of demonstrations and clashes with police across the country, in Granada, Valencia and Madrid.
Spanish Prime Minister Pedro Sánchez has condemned the violence, but there is no indication that protests will subside.
A young woman is said to have seriously injured her eye as a result of a police intervention in Barcelona over the weekend, according to AFP.
The incident has stirred up the mood between protesters and police even more.
There are also reports of looted and vandalized shops and hotels.
Rapper sentenced to prison
Protesters are protesting in support of rapper Pablo Hasél, who in 2018 was convicted of glorifying terrorism and insulting the royal family for what he wrote on Twitter but also in lyrics, including about the Basque terrorist group ETA and the terrorist group GRAPO.
Last week, Hasél was arrested in Lleida after the deadline to surrender to serve a nine-month prison sentence expired.
The arrest of the rapper was the trigger for the unrest.
But many protesters say the protests are about dissatisfaction with the government in Madrid in general, about freedom of expression and Catalonia's independence.