The Corriere della Sera newspaper on Wednesday quoted from a letter it said Francis wrote to Maduro on Feb. 7, several days after the socialist leader said in an interview that he had written to Francis to ask the pontiff's help in launching talks with the opposition.
A Vatican spokesman, Alessandro Gisotti, said the Holy See "doesn't comment on the letters of the Holy Father, which, obviously, are private in character."
Massimo Franco, the Corriere columnist who wrote the article, showed The Associated Press of copy of the letter he said Francis sent to Maduro.
On Monday, a delegation representing Venezuelan opposition leader Juan Guaido met at the Vatican with Holy See officials.
The Argentine-born Francis has lamented that Venezuelan bishops were frustrated in their efforts to help defuse political and social tensions in the country, where much of the population lacks adequate food and medicine. The letter to Maduro indicated the pope also felt frustrated by what he described as an inadequate government response to the willingness by church officials to facilitate dialogue aimed at achieving reconciliation in Venezuela.
Lamentably, the letter said, all intentions aimed at reconciliation begun in recent years were effectively thwarted since, despite various meetings, "there was no follow-up with concrete gestures" to implement agreed-upon measures.
Francis has said he favors dialogue, but only when it places the common good over all other interests and when it is aimed at achieving unity and peace.
Despite the diplomatic language in the letter, Francis is "quite tough in saying, 'Yes, I can be a mediator, but at my conditions,'" Franco told the AP in an interview.
In the letter, Francis appears to acknowledge Maduro is no longer recognized as president by many countries following a heavily criticized 2018 presidential election. The salutation refers to the Venezuelan as "Mr. Nicolas Maduro" and not as "president."
Maduro, paying a call on the pope at the Vatican in 2013, a few months after Francis became pontiff and shortly after the Venezuelan was elected president, received the pope's blessing.