ABOARD THE PAPAL PLANE (Reuters) - Pope Francis said he hoped U.S. President Donald Trump would re-think his decision to end a program protecting undocumented immigrant children, saying it was important for young people to have roots.

Pope Francis talks to journalists during a press conference aboard a plane flight to Rome at the end of his visit to Colombia, September 11, 2017. REUTERS/Andrew Medichini/Pool

“One hopes that it is re-thought somewhat,” Francis said on Sunday in answer to a question on the plane returning from Colombia about the program started by his predecessor 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 Trump’s decision.

Trump’s move this month to end the five-year-old program instituted by former President Barack Obama plunged almost 800,000 young people, known as “Dreamers,” into uncertainty.

It drew criticism from business and religious leaders, mayors, governors, Democratic lawmakers, unions and civil liberties advocates. Trump said during his election campaign he would end DACA if he became president.

Last week, 15 states and the District of Columbia filed a lawsuit challenging Trump’s decision.

It claims his decision was “motivated, at least in part, by a discriminatory motive” against Mexicans, who are the largest beneficiary of the program. It points to his statements from the 2016 presidential campaign..

“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,” Francis said.

“The relationship between a young person and his roots is very important. Young people who have been uprooted today are asking for help,” he said.

He appeared to take a swipe at 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 Trump over immigration issues, such as the president’s intention to build a wall on the border with Mexico and deport undocumented aliens.

Francis, the first Latin American pope, has made defense 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”.

Trump, who grew up in a Presbyterian family, shot back saying it was “‘disgraceful” for the pope to question his faith.

Trump met the pope at the Vatican during a tour of the Middle East and Europe last May.