Photo by Andrew Harrer-Pool/Getty Images President Donald Trump's former White House chief of staff John Kelly, a retired Marine Corps general, defended former Secretary of Defense Jim Mattis Thursday after Trump blasted Mattis on Twitter Wednesday night. Trump claims that he fired Mattis and asked for his resignation, two points that Kelly refuted in an interview with The Washington Post, during which he suggested the president might be "confused" and called Mattis an "honorable man." The president's tweets criticizing Mattis followed a scathing statement by Mattis earlier Wednesday accusing Trump of dividing the nation in a time of unrest. Visit Business Insider's homepage for more stories. President Trump's former White House chief of staff John Kelly defended former Secretary of Defense Jim Mattis Thursday, calling him an "honorable man" and refuting the president's claim that he fired the retired Marine Corps general. "The president did not fire him.