The U.S. ambassador to the Vatican says he expects Pope Francis will call on the U.S. to rediscover the fundamental values "that made our nation great" — including its long history of welcoming foreigners — when he visits next month and becomes the first pope to address Congress.

In an interview Tuesday with The Associated Press, Ambassador Kenneth Hackett said he expected migration, income inequality, family problems and the environment to be raised by Francis during his Sept. 22-27 visit to Washington, New York and Philadelphia.

Hackett said: "I'm not worried about the tense moments, really. In my two years here I've come to realize that Pope Francis will say and do what he wants. And that, people find refreshing even if they disagree with him."