Donald Trump is hitting back at the former defense secretary who called him "beyond repair" when it comes to national security.
Robert Gates served under presidents of both parties. He wrote in the Wall Street Journal on Saturday that Trump is "stubbornly uninformed" about the world.
Trump first swiped back on Twitter, then went further at an evening rally in Colorado Springs, Colorado.
The Republican nominee suggests that Gates "probably has a problem we don't know about" and claims that he would be "so much better at what he's doing" than Gates.
Trump also called the former secretary of defense "a nasty guy" and "an absolute clown." And he said, "I don't like critics."
Earlier Saturday, Trump addressed the Remembrance Project in Houston. That's an organization founded to advocate for tougher immigration laws in honor of those killed by people in the country illegally. Trump says he is "shining a national spotlight" on Americans killed by immigrants living in the United States illegally.
The Republican nominee says "not one more American life should be given up in the name of open borders."
Trump told the group most "politicians ignore your cries, but I never will."
The Republican nominee has appeared with the group before and has made its cause part of his platform. But his position on immigration has shifted repeatedly in recent weeks.