WASHINGTON (AP) — President Donald Trump has announced that Defense Secretary Jim Mattis will retire at the end of February.

Trump says on Twitter that a new secretary of defense will be named soon.

Trump’s announcement comes a day after he surprised U.S. allies and members of Congress by announcing the withdrawal of U.S. troops from Syria.

“General Jim Mattis will be retiring, with distinction, at the end of February, after having served my Administration as Secretary of Defense for the past two years. During Jim’s tenure, tremendous progress has been made, especially with respect to the purchase of new fighting….equipment. General Mattis was a great help to me in getting allies and other countries to pay their share of military obligations. A new Secretary of Defense will be named shortly. I greatly thank Jim for his service!”