A letter purporting to be from Italy\'s radical left-wing Red Brigades called on Friday for new attacks against politicians, bankers and reporters, just days after the president warned the country risked a return to the political violence of the 1970s. \"The dawn of the new revolution is here,\" read the letter, which was delivered to Il Giornale in Milan, the newspaper\'s website said. Il Giornale is owned by former Premier Silvio Berlusconi\'s brother, Paolo. It is the second letter in as many days allegedly written by the Red Brigades and sent to the media. Neither has been authenticated by authorities. ANSA news agency received a letter on Thursday purporting to be from the Red Brigades denying responsibility for a bombing of a school in southern Italy that killed a 16-year-old girl. The latest missive blamed the \"fascist state\" for last Saturday\'s bombing in Brindisi \"to placate the anger of the masses with fear.\" A turbulent social climate has developed in Italy as the economic crisis has deepened. There has been a series of attacks on the main tax collection agency in recent months, and an anarchist group claimed responsibility for shooting a senior nuclear industry executive in the leg earlier in May. The letter said the executive\'s shooting \"had reopened the games,\" listing politicians, in particular from Berlusconi\'s People of Liberty Party, bankers, and \"the journalists that serve\" them, as targets. The Red Brigades were responsible for numerous attacks in the 1970s, including the kidnapping and murder of former Christian Democrat Prime Minister Aldo Moro in 1978. The group has been revived several times, and murdered government labour adviser Marco Biagi in 2002. President Giorgio Napolitano warned on Wednesday that Italy risked falling back into the kind of political violence that scarred it during the 1970s.