Pope Francis gave advice on how to choose a president after U.S. Catholics expressed their concern about who to pick among the two candidates running for the White House. During a news conference on the plane returning from Azerbaijan on Sunday, Francis told Catholics to study, pray and then vote.

Francis' comments came as reporters at the freewheeling in-flight news conference asked him to share some wisdom that American Catholics should keep in mind before choosing between Republican Donald Trump and Democrat Hillary Clinton. 

"You have asked me a question that describes a difficult choice because, according to you, there are difficulties with one and difficulties with the other," the pope said, without naming the two running mates.

Francis said he would never interfere in an electoral campaign, saying “the people are sovereign. I would only say, study the proposals well, pray and choose with your conscience."

While stressing that he wanted to talk about a "fictional situation," Francis made some comments that apparently referred to the U.S. as being among the nations losing their culture of politics.

"When in any country there are two, three or four candidates who don't satisfy everyone, it means that perhaps the political life of that country has become too politicized and that it does not have much political culture," he said. "People say 'I'm from this party' or 'I'm from that party,' but effectively, they don't have clear thoughts about the basics, about proposals."

Last February, Francis reportedly intervened in the election campaign by speaking out against Trump's views on immigration, after the real estate mogul proposed to build a wall to keep Mexicans out of the United States. At the time, the pope said that a person with such views was "not Christian."

Later Trump responded to the pope's comments, calling them "disgraceful."

The two presidential candidates are deeply divided on major issues, including immigration, gun rights, LGBT rights and abortion and reproductive health care.

On Sunday, former New York Mayor Rudy Giuliani may have hinted that Trump would make a better president when he said that “everybody” commits infidelity, igniting a backlash on Twitter. He also brought up Clinton’s record on human rights.

“A woman who pretends to be a feminist shouldn’t be taking money from countries where women are stoned, where women are killed for adultery, and women can’t drive,” Giuliani reportedly said. “She’s taken hundreds of millions from those countries.”