After Trump’s Tweet, US Defence Secretary James Mattis Announces Resignation

Washington: US Defence Secretary James Mattis has announced that he would resign at the end of February due to differences with Donald Trump over the withdrawal of troops from Syria and Afghanistan, saying in a parting letter that the President deserves someone atop the Pentagon "better aligned" with his views.

The retired Marine general's announcement came on Thursday, a day after the Trump administration said that the full withdrawal of US forces from Syria was under way, a move that shocked American allies.

Trump overruled his advisers, including Mattis, over Syria troop withdrawal and declared victory over the Islamic State. However, the Pentagon and State Department for months have been saying the fight against the group in Syria was far from over, the Washington Post reported.

The President also ordered the Pentagon, against Mattis' recommendation, to come up with a plan to pull out approximately half of the 14,000 American troops deployed to Afghanistan, a move likely to plunge the war-torn nation into further chaos.

Mattis mentioned some of his differences with the President in the parting letter he submitted to the White House.

The retired general, in contrast to Trump, favoured international alliances and said that the US derives its strength from its relationships with allies and should treat them with respect. He also said the country must also be "clear-eyed" about threats, including from groups such as the Islamic State.

"We must do everything possible to advance an international order that is most conducive to our security, prosperity and values and we are strengthened in this effort by the solidarity of our alliances," Mattis wrote. 

The Pentagon released the resignation letter moments after Trump announced on Twitter that Mattis would be leaving, saying the already retired Marine would "retire". Trump made no mention of his differences in opinion with Mattis.

"General Jim Mattis will be retiring, with distinction, at the end of February, after having served my administration as Secretary of Defence for the past two years," Trump tweeted. 

"During Jim's tenure, tremendous progress has been made, especially with respect to the purchase of new fighting 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 Defence will be named shortly," he said.

House Minority Leader Nancy Pelosi said she was "shaken" by the resignation and described it as "very serious for our country".

Republicans were also dismayed by the decision. Senate Majority Leader Mitch McConnell said the US must maintain its carefully built alliances and a clear understanding of its friends and foes.

Matts was seen as a bulwark against Trump's "isolationist impulses" and extreme proposals. He served as a calm "reassurer-in-chief" while the President sent out provocative tweets, the Washington Post said. 

His departure led to a chorus of concern about the President's temperament and decision-making ability and injected new uncertainty into the administration's approach to global threats.