Waltz served as Trump’s national security adviser until Thursday, when the president announced he was moving Waltz to be the next ambassador to the U.N.

Asked whether U.S. citizens and noncitizens both deserve due process as laid out in the Constitution, Trump was noncommittal.

Trump was furious Sunday at what he called a "weak" case on his behalf from Media Buzz's Howard Kurtz, and called for the Fox host to retire.