Speaking to reporters as he flew back to Rome after several days in Colombia, Francis said that Trump’s decision to end legal protections for people brought to the country illegally as children would split families, “the cradle of life.”

“I have heard the president of the United States speak,” the pope said, according to news accounts.

“He presents himself as a pro-life man. If he is a good pro-lifer, he should understand that the family is the cradle of life and you must defend its unity,” the pope said.

Trump said last week he had decided to terminate the Deferred Action for Childhood Arrivals program in six months. He urged Congress to replace it in that time.

The Obama-era measure provides work permits and other legal documents to 800,000 young immigrants who were brought to the United States illegally as children, and protects them from deportation.

“Removing young people from their family is not a thing that bears good fruit, neither for the young person nor the family,” the pope said.

Francis has previously criticized Trump’s eagerness to build a wall along the U.S. border with Mexico and his decision to withdraw from the Paris climate accord.

During the presidential campaign last year, the pontiff said a person “who only thinks about building walls” is “not Christian.”

Trump responded that it was “disgraceful” for the pope to question his faith.