Dec. 22 (UPI) -- Brett McGurk, the special presidential envoy against the Islamic State, has resigned over the president's call to withdraw all troops from Syria.
McGurk, who has been also been a key figure in U.S. involvement in Iraq and Syria during the past three administrations, submitted his letter of resignation Friday, officials said.
CBS News was the first to report McGurk's resignation.
Defense Secretary Jim Mattis resigned a day earlier, citing differences of opinion with Trump in his resignation letter.
Trump decided Wednesday to quickly pull about 2,000 service members from the country in a full withdrawal, signaling a major Middle East policy shift that went against advice from his military and national security advisers.
"I think it's fair to say Americans will remain on the ground after the physical defeat of the caliphate, until we have the pieces in place to ensure that that defeat is enduring," McGurk said during a State Department briefing last week. "It would be reckless if we were just to say, 'Well, the physical caliphate is defeated, so we can just leave now.' I think anyone who's looked at a conflict like this would agree with that."
Trump cited "historic victories against ISIS," in a Twitter video message about his decision Wednesday. He again defended the move Saturday on Twitter.
"When I became President, ISIS was going wild," Trump tweeted. "Now ISIS is largely defeated and other local countries, including Turkey, should be able to easily take care of whatever remains."