Donald Trump has called the U.S. military a “disaster.” The head of the Air Force says he’s wrong.

“I can tell you the United States military is not any sort of disaster,” U.S. Air Force Secretary Deborah Lee James said in an interview with the Fortune Unfiltered podcast. “It is the best military on the planet.”

James, just the second woman to ever be Air Force Secretary, cited Russia as the greatest national security threat to the U.S. Tensions with Moscow, the battle to retake the Iraqi city of Mosul from ISIS, the humanitarian crisis in Syria, and heightened activity by China in the South China Sea all make for what she called “the most complex period we have ever faced during the three decades I’ve been on the scene.”

Subscribe to the Fortune Unfiltered podcast here, and read more about her interview on Fortune.com.

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