Pope Francis hopes President Donald Trump will re-think his decision to end a program protecting undocumented immigrant children, saying it was important for young people to have roots.
"One hopes that it is re-thought somewhat," Pope Francis said on Sunday in answer to a question about the programme started by former President Barack Obama and known as Deferred Action on Childhood Arrivals (DACA).
He spoke about DACA and the problems of immigrant families in general, adding that he wanted to learn more about President Trump's decision.
President Trump's move this month to end the five-year-old program instituted by President Obama plunged almost 800,000 young people, known as "Dreamers", into uncertainty.
It has drawn criticism from business and religious leaders, mayors, governors, Democratic lawmakers, unions and civil liberties advocates.
"In the end, young people feel like they have no hope. And who robs them of hope? Drugs, other addictions, suicides - youth suicides are very high - and this happens when they are torn from their roots," Pope Francis said.
He appeared to take a swipe at President Trump when he said: "The president of the United States ... presents himself as a man who is pro-life. If he is a good pro-lifer, he understands that the family is the cradle of life and you have to defend its unity."
The Pope has already clashed with President Trump over immigration issues, such as the president's intention to build a wall on the border with Mexico and deport undocumented aliens.
Pope Francis, the first Latin American pope, has made defence of immigrants a major plank of his papacy. The pontiff said during the presidential campaign that a man who thought about building walls and not bridges was "not Christian".
President Trump, who grew up in a Presbyterian family, shot back saying it was "'disgraceful" for the pope to question his faith.
Pope Francis also touched on climate change, saying a passage from the Bible's Old Testament that dismisses men as "stupid" is the best way to describe deniers.
"Why are we waiting to acknowledge the effects of climate change?" Pope Francis asked reporters. "I am reminded of a phrase from the Old Testament, from the Psalm: 'Man is stupid'."
"Those who deny [climate change] should go to scientists and ask them," Pope Francis said. "They speak very clearly, scientists are precise. We can see the effects of climate change and scientists clearly say what path we should follow."