An Italian court convicted former high-ranking state officials and mob bosses on Friday for holding secret negotiations in the early 1990s following a devastating wave of mafia murders and bombings.

Speaking in a high-security "bunker" courtroom on the outskirts of Palermo, Judge Alfredo Montalto ruled that the negotiations had damaged the interests of the state as he shed light on one of the murkiest chapters in recent Italian history.

After the verdict, members of the public clapped and cheered the prosecutors who brought the case to trial five years ago, two decades after a string of mafia bombs and assassinations killed 23 people, including prominent anti-mafia magistrates Giovanni Falcone and Paolo Borsellino.