Pope Leo last May became the first US leader of the global Catholic Church, but for ​the initial 10 months of his tenure, he mostly avoided comment about his home country and never once mentioned President Donald Trump publicly.

In recent weeks, the pope has emerged as a sharp critic of the Iran war. He named Trump, for the first time publicly, on Tuesday in a direct appeal urging the president to end the expanding conflict.

It is a significant shift in tone and approach that experts said indicated that the pope wanted to serve as a counterweight on the world stage to Trump and ​his foreign policy aims.

“I don’t think he wants the Vatican to be accused of being soft on Trumpism because he’s an American,” said Massimo Faggioli, an ​Italian academic who follows the Vatican closely.

Leo, known for choosing his words carefully, urged Trump to find an “off-ramp” to end the war, using ⁠an American colloquialism the president and administration officials would understand.

“When (Leo) speaks, he’s always careful,” said Faggioli, a professor at Trinity College Dublin. “I don’t think that was an accident.”

Chicago ​Cardinal Blase Cupich, a close ally of Leo, told Reuters the pope was taking up the mantle of a long line of pontiffs who have urged world leaders to ​turn away from war.

“What is different … is the voice of the messenger, for now Americans and the entire English-speaking world are hearing the message in an idiom familiar to them,” said the cardinal.

Pope says God rejects prayers of war leaders

Two days before appealing to Trump directly, Leo said God rejected the prayers of leaders who start wars and have “hands full of blood”, in unusually forceful remarks ​for a Catholic pontiff.

Those comments were interpreted by conservative Catholic commentators as aimed at US Defence Secretary Pete Hegseth, who has invoked Christian language to justify the joint US-Israeli ​strikes on Iran that initiated the war.

They also led to one of the Trump administration’s first direct responses to a comment by Leo.

“I don’t think there is anything wrong with our military ‌leaders or ⁠with the president calling on the American people to pray for our service members,” White House spokesperson Karoline Leavitt said, when asked about the pope’s remarks.

Marie Dennis, a former leader of the international Catholic peace movement Pax Christi, said Leo’s most recent comments and his direct appeal to Trump “reflect a heart broken by unrelenting violence.

“He is reaching out to all who are exhausted by this unrelenting violence and are hungry for courageous leadership,” she said.

Pope ramping up criticism for weeks

Leo had previously taken aim at Trump’s hardline immigration ​policies, questioning whether they were in line with ​the Church’s pro-life teachings. In those comments, which drew backlash from conservative Catholics, he refrained from naming Trump or any administration official directly.

The pope also carried out a major shake-up of US Catholic leadership in December, removing Cardinal Timothy Dolan as archbishop of New York. Dolan, seen as a leading conservative among ​the US bishops, was replaced by a relatively unknown cleric from Illinois, Archbishop Ronald Hicks.

Leo has been ramping up his ​criticism of the Iran ⁠war for weeks, as he said on March 13 that Christian political leaders who start wars should go to confession and assess whether they are following the teachings of Jesus. On March 23, Leo said military airstrikes were indiscriminate and should be banned.

Cardinal Michael Czerny, a senior Vatican official, said the pope’s voice would carry weight globally because “everyone can perceive that he speaks … for the common ⁠good, for ​all people and especially the vulnerable.”

“Pope Leo’s moral voice is credible, and the world wants desperately to ​believe that peace is possible,” said the cardinal.

Leo on Thursday began four days of Vatican events leading up to Easter Sunday, when he will deliver a special blessing and message from the balcony of St. Peter’s ​Basilica.

One of the most closely watched appointments on the Vatican’s calendar, the Easter speech is usually a time when the pope makes a major international appeal.