Pope Francis compared the border wall going up between the U.S. and Mexico to the Berlin Wall built in 1961 to keep East Germans from escaping into West Berlin and freedom.

Asked by Mexican reporter Valentina Alazraki what he thought of the Trump wall and of children being separated from the parents at the border, the pope said that building the wall is a mistake.

“I do not know what is going on with this new culture that defends territories by building a wall,” the pope said in a lengthy Spanish-language interview published Tuesday by Vatican News. “We already dealt with one, the one in Berlin, which brought us enough headaches and enough suffering.”

“But it seems that man does what animals do not do, right?” he continued. “Man is the only animal that falls into the same hole twice. We are repeating the same thing, right? Building walls as if that were a defense.”

“When defense is really dialogue, growth, welcome and education, integration, or the healthy limit of ‘that’s as far as we can go,’ but it’s human,” he said.

The pontiff, who is the ruler of the only completely walled-in country in the world and the smallest independent state by both area and population, said that he was not only referring to the U.S.-Mexico border here but of “all the barriers that exist.”

The pope also had severe words regarding the separation of children from their parents.

“And separating kids from their parents goes against the natural law, and those are Christians. But they cannot really be. It’s cruel. It falls into the greatest cruelty,” he said.

“To defend what? The territory or the economy of the country or who knows what, right? But they are ways of thinking that are applied to politics and they turn out a policy like this. It’s very sad,” he said.

“Whoever builds walls ends up as a prisoner of the walls he has built,” he said.

This is not the first time that Pope Francis has spoken out against the proposed U.S. border wall. Back during the 2016 election campaign the pope suggested that anyone who thinks of building walls instead of building bridges is no Christian.

Asked at the time about the pope’s comment in a town hall interview with CNN’s Anderson Cooper, Mr. Trump said he had no intention of fighting with Pope Francis, but he did remind the audience that the pope has “an awfully big wall at the Vatican.”

The massive, 40-foot high walls surrounding Vatican City State were built by an earlier pope, Leo IV, after Islamic Saracen troops sacked Old St. Peter’s Basilica in 846 AD.

The original wall encompassed the entire Vatican hill, surrounding what came to be known as the Leonine City, but was later reduced to circumscribe the 110-acre Vatican City that exists today.

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