The US Defence Secretary is going to retire in February.
James Mattis says he's going to step down so he can be replaced by someone whose views are "more aligned" with those of President Donald Trump.
He says the US needs to maintain strong alliances and show allies respect and be unambiguous towards countries like China.
President Trump said his replacement will be announced shortly.
He also thanked Mr. Mattis for his service:
....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!
— Donald J. Trump (@realDonaldTrump) December 20, 2018