WASHINGTON (AP) — Brett McGurk, the U.S. envoy to the global coalition fighting the Islamic State group, has resigned in protest over President Donald Trump's abrupt decision to withdraw U.S. troops from Syria, a U.S. official said, joining Defense Secretary Jim Mattis in an administration exodus of experienced national security figures.

Only 11 days ago, McGurk had said it would be "reckless" to consider IS defeated and therefore would be unwise to bring American forces home. McGurk decided to speed up his original plan to leave his post in mid-February.

Appointed to the post by President Bar...