(ANSA) - Naples, March 8 - Demonstrators and police clashed outside the offices of Naples newspaper Il Mattino Wednesday while anti-immigrant, anti-euro Northern League leader Matteo Salvini was inside addressing a forum. The protesters shouted slogans against the formerly secessionist leader, who has turned his party into a nationwide one but still regularly gets barracked in southern Italy. "I'm ready to challenge (ex-premier and likely future premiership candidate Matteo) Renzi (of the ruling centre-left Democratic Party) and govern Italy better from tomorrow," Salvini told the forum. He issued a message for Neapolitans: "Let's get to know one another, let's learn to respect each other". The demonstrators were from leftist and anarchist squats known as 'social centres' in Italy.