Secretary of State Marco Rubio met with Pope Leo at the Vatican on Thursday, an audience that follows President Donald Trump’s criticism of the first American pontiff over the Iran war.

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The closed-door meeting was the first between the head of the Catholic Church and a Trump cabinet official in nearly a year.

It comes at a fraught time between Washington and the Holy See, with relations at a low after weeks of presidential attacks on Leo and the Chicago-born pope’s outspoken responses.

Asked by reporters Tuesday if he was going to the Vatican to “smooth things over with the Pope,” Rubio, a practicing Catholic, said the trip had been planned before and “obviously we had some stuff that happened.”

He said there was “a lot to talk about” with the Vatican, including humanitarian aid for Cuba and concerns over religious freedom around the world.

The U.S. ambassador to the Holy See, Brian Burch, told journalists Tuesday that the conversation between the pope and Rubio was likely to be “frank.”

Rubio was also due to meet with the Vatican secretary of state, Cardinal Pietro Parolin, who strongly defended Leo and criticized Trump’s comments. “Attacking him like that or criticizing what he does seems a bit strange to me, to say the least,” Parolin said Wednesday.

Trump has publicly disparaged Leo for criticizing the U.S.-Israeli war on Iran, calling the pontiff “weak on crime” and “terrible for foreign policy” last month, and telling him to “get his act together” and not be a politician. “I don’t want a Pope who thinks it’s OK for Iran to have a Nuclear Weapon,” Trump said.

The president also told NBC News last month that he was “not a big fan” of the pope, adding: “I don’t think he’s doing a very good job. He likes crime, I guess.”

Trump doubled down on his criticism this week ahead of Rubio’s visit.

“The Pope would rather talk about the fact that it’s okay for Iran to have a nuclear weapon, and I don’t think that’s very good,” Trump told right-wing radio talk show host Hugh Hewitt. He also claimed that Leo was “endangering a lot of Catholics.”

That suggestion stemmed from the president’s determination that Iran not have a nuclear weapon, Rubio said, which could be used “against places that have a lot of Catholics, and Christians, and others for that matter.”

Leo, who will mark his first year as the pontiff on Friday, has hit back.

The pope said he was not interested in a debate with Trump and had “no fear of the Trump administration” as he vowed to keep up his appeals for peace, which he said were rooted in the Gospel.

He has also rejected the idea that he supported nuclear weapons. “The Church has for years spoken out against all nuclear weapons, so there is no doubt about that, and so I simply hope to be heard for the sake of the word of God,” he said Tuesday.

“If anyone wishes to criticize me for proclaiming the Gospel, let them do so with truth,” he added.

Trump has refused to apologize to Leo and has added to controversy by posting an image on social media that appeared to depict himself as Jesus Christ. It was later deleted after backlash.

During a tour of Africa last month, Leo said that the world was being “ravaged by a handful of tyrants” and blasted leaders who spend billions on wars, even though he challenged any suggestion that the remark was a direct rebuke of Trump’s actions in Iran.

In earlier comments, Leo denounced the “delusion of omnipotence” that is fueling the U.S.-Israel war in Iran and demanded that political leaders negotiate peace. He has also called Trump’s threat to destroy the entire Iranian civilization “truly unacceptable.”

Leo had previously also criticized the Trump administration’s immigration policies.

America’s top diplomat will also meet with Italian Prime Minister Giorgia Meloni on Friday, a close Trump ally in Europe who has strongly defended the pope. Trump has criticized Meloni and other European allies for their lack of support for the Iran war.