Leo, the first American Pope, has called for a "deep reflection" in the US about how migrants are treated under Trump, cast the Trump administration as being "extremely disrespectful" to immigrants and criticised what he called "their inhuman" treatment.
"I do think that some of the things that have come out of the Vatican on the immigration question in particular have been troubling, and ultimately I disagree with it," Vance, a Catholic, said in an interview on Fox News' The Ingraham Angle show on Tuesday.
"What I tell the Catholic leadership I talk to who disagree with our immigration policies, you know, I'm not hostile about it. I invite them to have the conversation but I also encourage them to remember that mass migration has victims."
Trump has pursued a hardline immigration crackdown and deportation drive that rights groups say has violated free speech and due process rights and created an unsafe environment, particularly for ethnic minorities, who have expressed concerns about racial profiling.
Trump, who has also been critical of Leo, says he aims to improve domestic security and curb illegal immigration.
Leo has also been critical of other policies that Trump has pursued.
The Vatican has declined to join Trump's so-called "Board of Peace" initiative for Gaza.
The Pope has criticised the Iran war that began on February 28 when the US and Israel launched strikes on Iran and recently praised an interim deal between Washington and Tehran that he hoped will end the conflict.
