PALERMO, Italy: The most wanted Italian mafia boss, Matteo Messina Denaro, was arrested by armed police on Monday at a private hospital in Sicily where the fugitive since 1993 is being treated for cancer.

Messina Denaro, known by the monikers "Diabolik" and "'U Siccu" (The Skinny One), had been given a life sentence in absentia for his part in the murders of anti-mafia prosecutors Paolo Borsellino and Giovanni Falcone in 1992, crimes that shocked the country and sparked a crackdown on the Cosa Nostra.

Messina Denaro, 60, was escorted out by two uniformed Carabinieri police officers from the "La Maddalena" hospital in Palermo and into a waiting black van. He was wearing a brown fur-lined jacket, glasses and a brown and white woolly hat.

Court sources said he was being treated for cancer and underwent surgery last year, followed by a series of dates under a false name.

"We had a clue to the investigation and followed it through to today's arrest," Palermo prosecutor Maurizio de Lucia said.

Magistrate Paolo Guido, who was also in charge of investigations into Messina Denaro, said dismantling his network of protectors was key in reaching the result following years of work.

The second man who took Messina Denaro to the hospital was arrested at the scene on suspicion of aiding a fugitive.

Images on social media showed locals applauding and shaking hands with police in balaclavas as the minivan carrying Messina Denaro was driven away from the suburban hospital to a secret location.

Italian Prime Minister Giorgia Meloni travelled to Sicily to congratulate the police chiefs following the arrest. "We didn't win the war, we didn't defeat the mafia but this battle is important to win, and it's a huge blow to organized crime," she said.

Maria Falcone, sister of the murdered judge, echoed that sentiment.

"It proves that Mafiosi, despite their delusions of omnipotence, are ultimately doomed to defeat in the conflict with the democratic state," she said.

Messina Denaro is the son of a mafia boss and is from the western Sicilian town of Castelvetrano, which is close to Trapani.

The mafia was still being run in the region around Trapani, where he had his regional stronghold, according to police reports from last September.

Before going into hiding, he was well-known for his taste in expensive cars, well-tailored suits, and Rolex timepieces.

He is facing a life sentence for his involvement in bombings that occurred in Florence, Rome, and Milan in 1993 and left 10 people dead. Prosecutors also accuse him of being the sole or co-conspirator in a number of other slayings that occurred in the 1990s.

In 1993 he helped organise the kidnapping of a 12-year-old boy, Giuseppe Di Matteo, in an attempt to dissuade his father from giving evidence against the mafia, prosecutors say. The boy was held in captivity for two years before he was strangled and his body dissolved in acid.

The arrest comes almost 30 years to the day since police arrested Salvatore "Toto" Riina, the Sicilian Mafia's most powerful boss of the 20th century. He eventually died in jail in 2017, having never broken his code of silence.

"It is an extraordinary event, of historic significance," said Gian Carlo Caselli, who was a prosecutor in Palermo at the time of Riina's arrest.

Italy still struggles to control organized crime organizations whose tentacles reach far and wide despite the euphoria.

According to experts, the 'Ndrangheta, the Calabrian mafia, has supplanted Cosa Nostra as the most potent organized crime organization in Italy.

According to Federico Varese, professor of criminology at Oxford University, "there is a sense that the Sicilian Mafia is not as strong as it once was, especially since the 1990s, they have really been unable to enter the drug market and so they are really second-class to the 'Ndrangheta on that."