President Donald Trump announced on Thursday that Defense Secretary Jim Mattis will be stepping down from his position in February of next year.
In his resignation letter, Mattis said: "Because you have the right to have a Secretary of Defense whose views are better aligned with yours. ... I believe it is right for me to step down from my position."
His resignation comes just a day after Trump made public his decision to withdraw American troops from Syria, a move that was reportedly opposed by Mattis and other top security advisers.
In a tweet announcing Mattis' retirement, Trump said the secretary's replacement will be announced soon.