GENEVA — A top United Nations official joined the criticism of Donald J. Trump on Wednesday, warning that his election would threaten international stability.

While much of the recent furor against Mr. Trump has focused on a 2005 recording in which he made exceptionally vulgar remarks about women, the United Nations high commissioner for human rights, Zeid Ra’ad al-Hussein, focused attention back on Mr. Trump’s comments about deporting undocumented immigrants, barring Muslims from entering the country and employing torture tactics.

“If Donald Trump is elected, on the basis of what he has said already, and unless that changes, I think it’s without any doubt that he would be dangerous from an international point of view,” Mr. al-Hussein told reporters in Geneva.

Mr. al-Hussein emphasized that his office tried to stay out of politics, but he added that if an election could lead to an increased use of torture or to the persecution of “vulnerable communities in a way that suggests that they may well be deprived of their human rights, then I think it is incumbent to say so.”