Mayor's office replies that Marino never mentioned invitation from pope.

Pope Francis has stated that he did not invite Rome's mayor Ignazio Marino to join him on his historic visit to America, according to a report by Italian news agency ANSA.

"I did not invite Mayor Marino, is that clear?", the pope told journalists in terse tones, saying: "I asked the organisers and they didn't invite him either."

Pope Francis made his comments in reply to a question during the his return flight to Rome on 28 September, adding that Marino “professes to be Catholic” and travelled to US "of his own accord."

However the response from city hall was swift: "The mayor never said he was invited by Pope Francis." Marino's trip to Philadelphia to join the pontiff at the World Meeting of Families on 26 September “stemmed from a series of meetings with US authorities”, according to the statement, which concluded by suggesting that the confusion arose over a "mistaken question" which may have been posed "with the intention to create controversy."

Even before he departed, Marino's trip to the US was the subject of contention, coming as it did the month after his extended American vacation in August.

His predecessor Gianni Alemanno, who is under investigations for his involvement in the Mafia Capitale scandal, accused Marino of using the pope's visit as “an excuse to do another runner to the US.”

From the outset Marino has staunchly defended his trip, saying that his presence in the US was to “help Rome” by raising funds for the restoration of city monuments, and pointing out that his travel costs were borne by the Philadelphia city authorities.