The papal spokesman is stressing that Pope Francis often says build bridges, not walls, and that his remark while flying back from Mexico wasn't targeting U.S. presidential candidate Donald Trump.

Francis said Thursday that a person who advocates building walls for solutions is "not Christian." Trump, who has repeatedly called for a wall to divide the United States and Mexico, retorted it was "disgraceful" to question a person's faith.

The Rev. Federico Lombardi sought to clarify the issue Friday, telling Vatican Radio that Francis' comments were "in no way a personal attack nor an indication on how to vote."

Lombardi noted Francis often has advocated "building not walls, but bridges," especially regarding Europe, as it struggles to handle the arrival of hundreds of thousands of people fleeing war and poverty.