By Daniel Burke and Livia Borghese, CNN

ROME (CNN) - Pope Francis' crusade against corruption in the Catholic Church, including an overhaul of the scandal-scarred Vatican Bank, has put the new pontiff in the Italian mafia's crosshairs, according to two organized crime experts.

"The strong will of Pope Francis, aiming to disrupt the gangrene power centers, puts him at risk. He disturbs the mafia very much," Nicola Gratteri, a top anti-mafia prosecutor in Italy, told CNN on Thursday.

"I don't have precise information about a plan of the mafia against Pope Francis," Gratteri continued. "But if I did, I wouldn't say."

Gratteri, a deputy prosecutor in Reggio Calabria, a city in southern Italy, is a well-known foe of Calabria's notorious mafia, known as 'Ndrangheta.

The mob's anger with the Pope centers on the Vatican Bank, which the new pontiff has tried to reform, according to experts on the Italian underworld.

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Vatican officials were not immediately available for comment. Earlier on Thursday, a Vatican spokesperson strongly denied any concerns about the Pope's safety.

"The Holy See is not at all worried," the Rev. Federico Lombardi told the French wire service Agence I.Media. "These are the usual inventions."

In May, the Vatican Bank, officially known as the Institute for Religious Works, issued its first-ever report on money laundering, an apparent attempt to improve its financial transparency.

The 64-page report details the Vatican's efforts to crack down on money laundering in particular, though it made no mention of mafia connections. The report found six charges of "suspicious activity" within the past year.

In June, the Pope established a five-person papal commission to investigate the activities of the Vatican Bank, which has been under pressure from international finance authorities to clean up its murky business practices.

A month later, Italian prosecutors arrested a priest who worked as a financial analyst for the Vatican, accusing him of trying to help smuggle tens of millions of euros across Europe using a private plane in July 2012. That same month, two top officials at the Vatican Bank resigned, as Italian prosecutors continued their three-year investigation into the bank.

The Catholic Church and the Italian mafia have a long and complicated history, said Antonio Nicaso, an expert on organized crime in Italy and co-author with Gratteri of a new book called "Holy Water," which explores the relationship between mobsters and the church.

Underworld gangsters often paid for local church repairs or bankrolled feast day celebrations for Catholic saints, Nicaso told CNN. In exchange, Catholic officials kept silent about their illicit deeds.

"The church never raised the issue," he said. "The church has never excommunicated a mobster."

More recently, the mafia used the Vatican Bank to smuggle money, Nicaso said, though he offered no specific evidence. The Pope's reforms threaten that arrangement and will anger organized crime, he added.

"We believe that this is an unprecedented challenge to the economic power center of the Vatican, and for that reason he may face some kind of risk," Nicaso said.

The Vatican has strongly denied any ties to the Italian mafia at the Vatican Bank or at any other church institution.

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The Pope's penchant for wading into the massive crowds who attend his speeches and events poses a particular security risk, Nicaso said.

"He has to be more cautious. He can't go walk around Vatican Square anymore like he's a normal person."

Asked if the mafia would dare try to assassinate such a popular figure, Nicaso said, "There are so many ways to kill a pope. They have to be careful. But in the history of organized crime, whenever they had to remove an obstacle, they never thought about the consequences."

In addition to the Vatican reforms, Francis in his speeches has taken aim at corruption, saying on Monday, for example, that a Christian "who gives to the church with one hand but steals with the other hand from the country, from the poor, is unjust."

The Pope then paraphrased Jesus, saying that it would be better for a corrupt person "if a millstone were put around his neck and he be thrown into the sea."

"He is changing the church," Nicaso said. "It is not a church of power and luxury anymore, and his promise to restructure [the Vatican Bank] is like a Copernican revolution."