WASHINGTON, Dec. 23 (Xinhua) -- U.S. President Donald Trump announced Sunday that he has picked Deputy Secretary of Defense Patrick Shanahan as the acting Pentagon chief.

Shanahan will assume the role starting Jan. 1, 2019, Trump said in a tweet Sunday noon.

"Patrick has a long list of accomplishments while serving as Deputy, & previously Boeing. He will be great!" The president added.

The announcement came after Trump said earlier in the past week that current Defense Secretary Jim Mattis would "retire" at the end of February next year. Enditem