Authorities in Spain are braced for a fifth night of protests on Saturday over the imprisonment of a rap artist for glorifying terrorism and insulting royalty in his music and on Twitter. Organisers called for demonstrations in Madrid and Barcelona, where protests on previous nights featured clashes with police, property damage and looting. About 80 people have been arrested, including four on Friday night, and more than 100 people have been injured since the rapper, Pablo Hasél, was arrested on Tuesday in the north-east city of Lleida and taken away to begin serving a nine-month prison sentence. The disorder appears to have stemmed from a fringe group of mainly younger people who constituted a small number of the thousands who marched to support Hasél and to oppose the Spanish laws used to prosecute him. Police in Catalonia have reported at least three mob attacks on police stations. Rioters smashed their way into bank offices in downtown Barcelona, burned trash containers and looted sporting goods stores on Friday night. Barcelona’s mayor, Ada Colau, made an appeal for calm. “Defending the freedom of expression doesn’t justify in any case the destruction of property, frightening our fellow citizens, and hurting businesses already hurt by the crisis,” she said. At issue are more than 60 tweets published between 2014 and 2016 for which Hasél was given a nine-month prison sentence in 2018 for “glorification of terrorism”. He was also fined 25,000 euros ($30,000) for insults, libel and slander for tweets about the former king Juan Carlos I and for accusing police of torturing and killing demonstrators and migrants. On his Twitter account, the rapper paid homage to armed Spanish groups such Grapo, a Marxist “anti-fascist resistance” organisation accused of about 1,000 acts of violence between 1975 and 2003, including 80 murders and attempted murders, and various kidnappings. Hasél also tweeted about members of the now defunct Basque separatist organisation, Eta, which during four decades of violence killed at least 853 people in a campaign of car bombings and shootings. Amnesty International and Spanish celebrities, such as Javier Bardem and Pedro Almodóvar, say Hasél’s sentence – and other jailings – are having a chilling effect on freedom of speech in the country.