Head of the Roman Catholic Church Pope Francis on 24 may welcomed U.S. President Donald Trump to the Vatican for their first face-to-face meeting.
Trump arrived at the Vatican after stops in Saudi Arabia and Israel.
The two leaders have diametrically opposing views on issues as varied as immigration, climate change and arms sales.
According to the New York Times, on 23 may Cardinal Peter Turkson, a top Vatican official with close ties to Francis, acknowledged the differences in a post on Twitter: "Pope Francis & Pres Trump reach out to Islam-world to exorcise it of rel. Violence. One offers peace of dialogue, the other security of arms," he wrote, in an apparent reference to the $110 billion weapons sale that Mr. Trump concluded with Saudi Arabia.
In February last year, Pope Francis responded to a question about the President's hard line against immigrants and his desire to build a wall along the border with Mexico, telling reporters, "a person who only thinks about building walls, wherever they may be, and not building bridges, is not Christian."
Trump, a candidate at the time, swiftly returned fire. "For a religious leader to question a person's faith is disgraceful," he said at a campaign rally in South Carolina.
"No leader, especially a religious leader, should have the right to question another man's religion or faith. If and when the Vatican is attacked by ISIS, which as everyone knows is ISIS' ultimate trophy, I can promise you that the pope would have only wished and prayed that Donald Trump would have been president," he continued.