"We've made clear to them they need to undertake every effort they can to stop this illegal migration from entering the United States, and the president's made very clear they will not be permitted to enter our country unlawfully," Pompeo said on "Face the Nation" Sunday.
He disputed that Mr. Trump's emphasis on hardening his immigration policies in recent weeks was aimed at rallying his base.
"I've been involved in scores of conversations about stopping illegal immigration from Mexico and never once has there been a discussion of the political impact in U.S. domestic politics," Pompeo said. "It has always been about securing the safety of the American people and securing our southern border."