Pope Francis has revealed he was the target of an attempted suicide bombing during his visit to Iraq three years ago, the first by a Catholic pontiff to the country and probably the riskiest foreign trip of his 11-year papacy.

In an excerpt published on Tuesday from a forthcoming autobiography, Francis said he was informed by police after landing in Baghdad in March 2021 that at least two known suicide bombers were targeting one of his planned events.

"A woman packed with explosives, a young kamikaze, was heading to Mosul to blow herself up during the papal visit," wrote the pontiff, according to an excerpt from the book in Italian daily Corriere della Sera. "And a van had also set off at full speed with the same intent."

Francis' visit to Mosul was a key moment during his Iraq trip. Iraq's second-largest city had been under the control of Islamic State from 2014 to 2017. The pope visited the ruins of four destroyed churches there and launched an appeal for peace.

During the trip, the Vatican provided few details about the security preparations for the pope. Many of the events during his visit, which took place as the COVID-19 pandemic was first easing, were open only to a limited number of people.

Iraq is known to have deployed thousands of additional security personnel to protect Francis.

The Vatican did not immediately respond to a request for further details about the pope's new comments.

Francis' new autobiography, entitled "Hope", is due to be published on Jan. 14. The pope also published a memoir this March.

In the excerpt published on Tuesday, Francis said the Vatican had been informed about the assassination attempt by British intelligence.

The pope said he asked a security official the next day what had happened to the would-be bombers.

"The commander replied laconically: 'They are no more'," wrote Francis. "The Iraqi police had intercepted them and blown them up."