Italy's hard-line interior minister, Matteo Salvini, who is campaigning in the European elections on a strong anti-immigrant platform, jumped on the arrest with a message on Twitter, saying "eliminating illegal immigration to Italy and Europe is a moral duty: Everyone home."
Carabinieri investigating the arson said they were still identifying the suspect and his country of origin. It was not clear if he was a legal resident. ANSA said the suspect broke into the police station and set the fire. A motive was not clear.
Salvini has taken a hard line with migrant arrivals, forbidding most rescue ships from bringing migrants to Italian ports. As a result, arrivals are down by nearly 90 percent over last year, at 1,265 so far this year compared with 10,659 in the same period last year, according to Interior Ministry statistics. Tunisians represent the most arrivals, followed by Pakistan, Iraq and Algeria.