PALERMO, Italy, May 27 (Reuters) - Sicilian mob bosses and high-ranking Italian officials, both former and current, went on trial on Monday over allegations they held secret negotiations to stop a wave of deadly mafia bombings in the early 1990s.
The trial stems from a murky and tumultuous period in Italian history when the "Bribesville" corruption investigations t brought down the political establishment around the same time as a string of mafia bombs killed 21 people.
Prosecutors say the bombings stopped in 1994 after a deal brokered by Marcello Dell'Utri, a former senator and close associate of Silvio Berlusconi, who filled the vacuum left by the collapse of the old party system when he entered politics the same year.
Palermo judge Alfredo Montalto opened the trial in a high-security "bunker" courthouse near Palermo on the 20-year anniversary of a mafia car bomb attack near Florence's Uffizi Gallery that killed five people, including a newborn baby.
Prosecutors allege that senior politicians and police officials held talks with the mafia after judge Giovanni Falcone, his wife and three bodyguards were assassinated by a bomb under a road in 1992.
The state's willingness to enter talks after Falcone's murder encouraged further bombings, prosecutors say, and prompted the assassination of prosecutor Paolo Borsellino because he had learned of and opposed the negotiations.
In exchange for stopping the bombings, the Sicilian mafia wanted lighter sentences and better jail conditions for convicted gangsters.
"The state cannot sweep its responsibilities under the rug," prosecutor Antonino Di Matteo told reporters before Monday's hearing.
Berlusconi is not charged. Nicola Mancino, who was interior minister during the period of the alleged talks, is being tried for false testimony, while the other nine defendants, including Dell'Utri, face charges that they sought to blackmail the state.
All 10 defendants deny any wrongdoing.
Four mob chieftains face charges, including Sicily's former boss of bosses Salvatore "the Beast" Riina. Three were connected to the court by video link from their prisons while a fourth, turncoat Giovanni Brusca, observed from a secret location.
Vittorio Teresi, another prosecutor in the case, said on Monday that he would seek an additional charge against Mancino at the next hearing, to be held on Friday, for aiding the mob.
Mancino rejected the charges and said he should not stand trial in the dock along with mobsters.
"I fought against the mafia," he told reporters when he arrived at Monday's hearing. "I cannot be tried alongside mafiosi. I will ask to be tried separately." (Writing by Steve Scherer; Editing by Sonya Hepinstall)