Donald Trump has seemingly put his rivalry with Fox host Megyn Kelly on hold for the second time and is now in the midst of a rivalry with Pope Francis and the Vatican following comments issued by the Pope about the mogul's plan to build a wall between Mexico and the U.S. were he elected president.

The back-and-forth between the two began even before Pope Francis left for Mexico, when Trump referred to Francis as "a very political person."

"I don't think he understands the danger of the open border we have with Mexico," Trump said, according to The Washington Post. "And I think Mexico got him to do it because Mexico wants to keep the border just the way it is, because they're making a fortune and we're losing."

Vatican spokesman Rev. Federico Lombardi responded late Tuesday, saying that Trump's comments are founded on a lack of information while criticizing the Republican frontrunner for not being aware of the Pope's stance on immigration.

"The pope always talks about migration problems all around the world, of the duties we have to solve these problems in a humane manner, of hosting those who come from other countries in search of a life of dignity and peace," Lombardi said.

The feud seemed to settle, as neither the Vatican nor Trump had anything to say about the other during the Pope's time in Mexico. However, the feud was soon reignited during a press conference aboard the papal plane when Francis answered a question about Trump's plan to build a wall at the U.S.-Mexico border, The New York Times reported.

"A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian," the pope said in a press conference where he covered topics that included using contraception to avoid having fetuses contract the Zika virus. "This is not in the gospel."

Trump, not one to take such an attack lying down, immediately fired back, calling Francis' comments "disgraceful."

"No leader, especially a religious leader, should have the right to question another man's religion or faith," he said, according to The Independent. "If and when the Vatican is attacked by ISIS, which as everyone knows is ISIS's ultimate trophy, I can promise you that the Pope would have only wished and prayed that Donald Trump would have been president."

Though seemingly innocuous, the feud may have an impact on the Republican primary in the months to come. Trump's GOP opponents have a new source of ammunition just by the business mogul being part of a new rivalry, while Francis' comments open him up to the criticism that his papacy is too partisan and his policies are to liberal.

Neither the Pope nor the Vatican have issued a rebuttal to Trump's comment, but considering that one of Pope Francis' core ideologies in his papacy is tolerance and acceptance, it's likely that they will just leave well enough alone.