Defense Secretary Jim Mattis to retire, Trump says

U.S. President Donald Trump (L) and Defense Secretary James Mattis arrive for an event commemorating the 35th anniversary of attack on the Beirut Barracks in the East Room of the White House. (Photo by Chip Somodevilla/Getty Images)

President Donald Trump announced that Defense Secretary James Mattis will be retiring in the new year. He sent out a series of tweets on the matter. 

"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,' Trump said in the tweet. 

President Trump thanked Mattis for his service, and says a new chief will be named shortly.

"General Mattis was a great help to me in getting allies and other countries to pay their share of military obligations."

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.

The Associated Press Contributed to this report.