A death threat claiming to be from the Red Brigades and directed at Finmeccanica Chairman and CEO Giuseppe Orsi is a hoax, sources at the defence and aerospace giant said on Friday. \"Death to Orsi\" was scrawled in pencil inside the Genoa office of Ansaldo Energia, which belongs to the state-controlled Finmeccanica group, along with the Red Brigade\'s five-pointed-star symbol. The threat caused alarm as it came after last week\'s shooting in the leg of Roberto Adinolfi, the CEO of Ansaldo\'s nuclear unit, Ansaldo Nucleare, which a group called the Informal Anarchists Federation (FAI) claimed responsibility for. The sources said an internal probe \"had not identified the person responsible but had made it possible to rule out the possibility that the threat against Orsi is linked to subversive elements. \"So it should be considered the work of a mythomaniac,\" the sources added. The Red Brigades were responsible for numerous acts of terror during Italy\'s \'years of lead\' of political violence in the 1970s and 1980s. They murdered former Italian premier Aldo Moro in 1978. Various groups have tried to resurrect the Red Brigades, including the so-called new Red Brigades, who killed government advisors Massimo D\'Antona in 1999 and Marco Biagi in 2002 but are now thought to be defunct. Jailed members of the new Red Brigades praised the kneecapping of Adinolfi and called for \"revolution\" in court this week. Italian Premier Mario Monti was threatened in a letter Wednesday by a cell claiming to be part of the FAI, but police now suspect that was a hoax too. The government announced a plan Thursday to increase counter-terrorism intelligence and protection for potential targets in response to the threats and attacks. The interior ministry said that 14,000 sites are currently considered potential targets and more than 550 people are already under special government protection, many for mafia threats. The ministry stressed that roughly 20,000 military and police officers work in this area. Other possible targets of the anarchists include banks, ministries, police stations and prisons. Extreme acts have been on the rise in recent weeks in recession-hit Italy amid growing tension over government austerity measures aimed at putting Italy\'s public finances back in order. A businessman held a revenue-service clerk hostage for six hours in Bergamo earlier this month. Tax collection agency Equitalia has been hit by a string of letter-bomb and petrol-bomb attacks, including one at the weekend.