Jim Mattis officially resigned as Secretary of Defense on Monday, two months before his announced resignation date, with a farewell statement to employees citing Abraham Lincoln.
"Do not let anything that sees, changes, obstructs or delays your military movements or plans," wrote Mattis, citing the former president to all members of the Defense Department.
in the best possible hands. I am confident that each one of you will remain resolute in our sworn mission to support and defend the Constitution while protecting our lifestyle. Our department is proven to be the best when time is hardest. So keep the faith in our land and stand against our enemies alongside our allies.
"It has been a great honor to serve at your side. May God keep you safe in the air, on land and at sea.
Mattis has resigned this month after President Donald Trump had abruptly decided to send US troops out Syria's defense secretary's advice is that the move could exacerbate the problems in the region.
In a letter of resignation criticized as Trump's foreign policy, Mattis has set a departure date of 28 February. "Because you have the right, Defense Ministers, whose views on these and other issues are more attuned to yours, I believe it is right to step down from my position," wrote Mattis.
Trump forced the Pentagon boss Patrick Shanahan becomes deputy secretary of defense.
Mattis, known as "Mad Dog Mattis" during his naval career, served in the military for more than four decades, leading the US High Command from 2010 to 2013. He supported Trump in strengthening the military and reinforcing combat readiness.
Shanahan, as deputy minister of defense, focused on the internal Pentagon reform and creation of the space force promised by Trump.
Shanahan "has a deep understanding of military Operations and global security issues, and above all, he has the broad experience in the Corporate governance that enables him to effectively oversee the Department of Defense, "Reuters reported, citing a high-ranking administrative official.