Defence Secretary James Mattis, who batted for strong Indo-US military ties, has resigned, citing irreconcilable policy differences with Donald Trump after the US President shocked the Pentagon by deciding to withdraw American troops from strife-torn Syria. Mattis, latest in a string of senior US officials to quit the Trump administration, in a letter to the president said that he should choose a person who is more in tune with his world view. Trump announced the resignation in two tweets on Thursday evening, and said Mattis, will leave at the end of February.

According to reports, 68-year-old Mattis, a retired United States Marine Corps General, went to the White House on Thursday afternoon in a last attempt to convince Trump to keep US troops in Syria. He was rebuffed, and told the president that he was resigning as a result. Separately on Thursday, there were reports the White House was also planning a sharp cut to troop numbers in Afghanistan. In his extraordinary resignation letter, Mattis told Trump he had "the right to have a Secretary of Defence whose views are better aligned with yours".