Trump fires Secretary of Defense Mark Esper

President Trump on Monday said he fired Secretary of Defense Mark Esper and that Christopher Miller, the director of the National Counterterrorism Center, will take over as acting defense secretary "effective immediately."

“Mark Esper has been terminated,” Trump tweeted, his first ousting of a Cabinet official since the election was called for Democratic nominee Joe Biden. “I would like to thank him for his service.”

A senior U.S. official told Fox News that White House chief of staff Mark Meadows called Esper and let him know he was being fired before the president’s tweet.

Fox News has learned that Esper was involved in meetings at the Pentagon Monday morning, and was behaving as defense secretary. Sources told Fox News that the president's announcement caught some of his staff off guard.