About 200 protesters gathered in front of the Opera prison in Milan on Saturday to demand the release of anarchist Alfredo Cospito, who has been on a hunger strike for months, the Italian Rai News 24 TV channel said.
Cospito is striking against the prison regime called 41-bis, which involves solitary confinement in cells even smaller than the typical type used to house prisoners. It is reserved for inmates who are deemed dangerous even when inside prison.
Cospito has reportedly lost around 100lbs (45kg) since his hunger strike began more than 100 days ago.
After the protesters threw rocks and smoke grenades at the prison, they were rebuffed by law enforcement.
Another unauthorized demonstration was held in Rome on Saturday. Italian police said about 800 people gathered in the capital city and attempted to construct barricades in order to block one of the major roads. The protest ended in clashes with police. At least two protesters were injured.
According to Rai News 24 TV, three people were detained.
Cospito is serving time for shooting the head of an Italian nuclear energy company in the knee and for bombing the Carabinieri cadet barracks in Fossano in 2006. No one died in the bombing and the head of the Italian energy company survived the attack. Cospito was sentenced to ten years in prison for the shooting and life without parole for the bombing.