Pope Francis said US Republican presidential candidate Donald Trump is "not Christian" because of his views on immigration. Trump later replied that the Pope's remarks were "digraceful," reports the ABC.
In a freewheeling conversation with reporters on his flight back to Rome from a visit to Mexico, Pope Francis was asked about Mr Trump and some of his statements, such as vowing to build a wall between the United States and Mexico if he becomes president.
"A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian," the Pontiff said.
"This is not in the Gospel."
His remarks drew swift condemnation from the outspoken Republican presidential candidate, who described them as "disgraceful."
"No leader, especially a religious leader, should have the right to question another man's religion or faith," Mr Trump said in a statement that he read out to a crowd at a campaign stop in South Carolina.
"I am proud to be a Christian and as president I will not allow Christianity to be consistently attacked and weakened."
Mr Trump added that the government in Mexico, where the Pope spent the past few days, should be ashamed of itself for using the Pope as "a pawn."
People of Mexico give Pope a fond farewell (Rome Reports)