ROME, April 22 (Reuters) - Italy will declassify secret documents about terrorist bombings between the 1960s and 1980s during a period known as the "Years of lead", the government announced on Tuesday.
The ultra-leftwing Red Brigades, neo-fascist groups, shadowy secret service figures and the mafia have all been implicated in the surge of political violence including the 1969 bombing in Milan's Piazza Fontana and the bombing of Bologna's main railway station in 1980.
Scores of people were killed and hundreds more injured, but many of the incidents, which took place during a Cold War period of extreme political tension, remain unsolved despite years of investigation.
Prime Minister Matteo Renzi said in a statement he regarded the decision to declassify the documents as "a duty towards citizens and relatives of the victims of episodes which remain a murky stain in our common memory."
He said documents relating to the Piazza Fontana and Bologna bombs, the mysterious crash of a DC-9 aircraft at Ustica near Sicily in 1980 and other bombings in the 1970s and 1980s would be opened to the public.
The documents will be declassified starting with the oldest and collected in the central state archives. (Reporting by James Mackenzie; Editing by Ruth Pitchford)