Pope Leo has dismissed the latest criticisms from President Donald Trump, saying neither he nor the Catholic church supports nuclear weapons, and that any critics should speak “truthfully”.

“But I guess it's up to the Pope. He thinks it's just fine for Iran to have a nuclear weapon,” the President said Monday in an interview with conservative radio host Hugh Hewitt.

But speaking on Tuesday evening as he departed the papal retreat at Castel Gandolfo, Leo pushed back against the White House, saying the “mission of the Church is to proclaim the Gospel, to preach peace.”

“If someone wants to criticize me for proclaiming the Gospel, let him do so truthfully,” he said.

“For years, the Church has spoken out against all nuclear weapons, so there is no doubt on that point,” he added.

The Pope again emphasized the importance of dialogue over further escalation in conflict.

“I always believe that it is much better to enter into dialogue, than to look for arms, and to support the arms industry, which gains billions and billions of dollars each year,” he said.

Leo has been a vocal critic of Trump’s war with Iran, repeatedly calling for an approach centered on diplomacy and dialogue.

Those criticisms have drawn Trump’s ire, with the President accusing the pontiff of being “weak on crime” and “terrible for foreign policy” after Leo called for a peaceful resolution to the conflict in the Middle East.

Steve Millies, a professor of Public Theology at the Catholic Theological Union in Chicago, tells TIME that Leo’s criticism—as the first American-born Pope—carries particular weight.

“Pope Leo has poked at the vulnerability of this Administration's argument for the war in Iran. Everyone in the world can see that the Administration didn't really make the case before the war. We can see that the war does not satisfy the criteria for a just war,” he says.

Secretary of State Marco Rubio is due to meet with the Holy See, the government of the Catholic Church, on May 7 at the Vatican to discuss a range of issues, including the conflict in the Middle East.

Asked Tuesday whether the trip was intended to repair relations with the Pope following Trump’s comments, Rubio rejected the suggestion.

“No, I mean, it’s a trip we had planned from before,” Rubio said during a White House press conference.

When asked about Trump’s accusation that the pontiff was “endangering Catholics,” Rubio insisted the President was not attacking the Pope directly.

“What the President basically said is that Iran can't have a nuclear weapon because they would use it against places that have a lot of Catholics, and Christians, and others,” Rubio said.

Millies says the visit is significant in maintaining ties between Washington and the Holy See.

“As a general matter, a new Administration always wants to make sure that this relationship is intact,” he explains. “The Holy See doesn't have a lot of physical power, it can't wage a war, it doesn't command an enormous amount of money, but the Church is everywhere, and diplomatically, the Holy See is very important even for a power like the United States.”

Trump’s criticism of the Pope, combined with a now-deleted AI-generated image depicting himself in a Jesus-like form, has generated backlash among Christians and conservatives.

A poll conducted at the end of April found that 87% of Americans disapproved of Trump’s post, while 66% responded positively to Leo’s calls for a peaceful resolution.

Millies says Trump appears to believe many Catholic voters–a voting bloc Trump won by 12 points in the 2024 Presidential election–will remain aligned with him politically despite the clash with the Pope.

“I do think there are Catholics for whom that's going to work, but for most Catholics, having the President of the United States attack the Pope over and over in this pointed way, pushes a button. It excites a reaction, and the reaction is not one that's going to play well for President Trump or for the Republican Party,” he says.

Leo, who marks his first year as Pope on Friday, said he hopes his meeting with Rubio will lead to “a good dialogue,” approached “with trust and openness,” in order “to understand one another well.”

Millies also emphasizes that the visit presents a political opportunity for Rubio, who is widely viewed as a potential Republican Presidential contender in 2028.

“Rubio's performance on this trip is something to watch closely, not only as the role of Secretary of State in trying to turn the temperature down and making it a little easier for Catholics to line up with the Republican Party," he says. "But also important, from Rubio's point of view, to note the contrast with how JD Vance pedantically lectured the Pope about theology.”