Italian anti-mafia police caught Sicilian godfather Matteo Messina Denaro on Monday, ending a 30-year manhunt for Italy's most wanted fugitive.

A ruthless operator who once reportedly boasted he could "fill a cemetery" with his victims, the 60-year-old was a leading figure in Cosa Nostra, the real-life Sicilian crime syndicate depicted in the Godfather movies.

The mobster was picked up "inside a health facility in Palermo, where he had gone for therapeutic treatment", special operations commander Pasquale Angelosanto said in a police statement.

He had been undergoing periodic treatment for colon cancer under a false name, and did not resist arrest, ANSA news agency said.

Messina Denaro was one of the mob's most brutal bosses, whose convictions included a life sentence given in absentia in 2020 for the 1992 murder of anti-mafia judge Giovanni Falcone.

He had been on the run since 1993.

While commentators debate how powerful he was in recent years, mafia expert Anna Sergi said his importance was as "the last one, the most resilient one, the 'purest' Sicilian mafioso remaining".

"He is the essence of the great historical power of Cosa Nostra," said Sergi, a criminologist at the University of Essex.

"The myths around his period on the run are part of the reason why the Mafia myth endures."

She said little was known about where he had been or how he stayed hidden, but noted: "A man among the most wanted in the world must have had protection."

Crucial battle

Italian Prime Minister Giorgia Meloni hailed the "great victory" against the "most significant" mafia boss, and immediately headed to Palermo to congratulate officials in person.

"It is a major blow for organised crime," she told reporters in the Sicilian capital.

"We haven't won the war, we haven't beaten the mafia, but this battle was a key battle to win."

Messina Denaro was one of the great bosses of the Sicilian Mafia, after Toto Riina and Bernardo Provenzano, who died in prison in 2017 and 2016 respectively.

He had been number one on Italy's most-wanted list, accused of mafia association, multiple murders and use of explosives.

On Monday he was escorted by officers to a waiting vehicle, wearing a hat and a brown leather jacket with a cream sheepskin lining, according to police images.

His first words to officers were "I'm Matteo Messina Denaro", ANSA reported.

Locals cheered and applauded in the rain as he was driven away from the Palermo clinic by police, according to police videos.

"For me today represents the end, the end of Cosa Nostra," said Palermo resident Giovanni Guarino.

"The old mass murder mafia that brought down this country (is over)."

Dissolved in acid

Among other crimes, Messina Denaro was convicted in absentia of being behind the 1993 bombings in Rome, Milan and Florence that killed 10 people.

He was also convicted for the murder of a teenager who was strangled and dissolved in acid after his father turned state witness.

The arrest of "an extremely dangerous fugitive" was "an extraordinary day for the state", Interior Minister Matteo Piantedosi said.

The net had been slowly tightening around Messina Denaro in the years before his arrest.

Investigators spent decades searching the homes and businesses of his known allies in Sicily, including for grottoes, caverns or even bunkers inside buildings where he could be concealed.

In 2015, police discovered he was communicating with his closest collaborators via the pizzini system, where tiny, folded paper notes were left under a rock at a farm.

Federico Varese, a criminology professor at Oxford University, said the fact that Sicilian mob families are weaker these days than their counterparts in Calabria or Campania may have helped in his capture.

He said it was "amazing that he was still in Palermo".

"But it makes sense. If you want to continue to exercise a degree of power, you must be in the territory," he said.