High-level defections continue to come after Donald Trump's decision

WASHINGTON - A top US envoy leading a global coalition fighting the Islamic State group has quit over US President Donald Trump's decision this week to pull US troops out of Syria, a source familiar with the matter said on Saturday.

Brett McGurk, US special presidential envoy for the global coalition to defeat the militant group, submitted his resignation effective Dec 31 to Secretary of State Mike Pompeo on Friday, a State Department official said.

In an abrupt policy shift, Trump announced on Wednesday that Washington would withdraw the roughly 2,000 US troops in Syria, upending a pillar of American policy in the Middle East and alarming US allies.

The decision was followed on Thursday by the surprise departure of US Secretary of Defense Jim Mattis, who in a resignation letter to Trump laid bare the growing divide between the two over foreign policy.

In an abrupt policy shift, Trump announced on Wednesday that Washington would withdraw the roughly 2,000 US troops in Syria, upending a pillar of American policy in the Middle East and alarming US allies.

Appointed to the post by President Barack Obama in 2015 and retained by Trump, McGurk said in his resignation letter that the militants were on the run, but not yet defeated, and that the premature pullout of US forces from Syria would create the conditions that gave rise to the IS group.

The resignation letter to Pompeo was submitted on Friday. The official was not authorized to discuss the matter publicly before the letter was released and spoke on condition of anonymity.

Trump played down the development, tweeting on Saturday night that "I do not know" the envoy and it's a "nothing event". He noted McGurk planned to leave soon anyway and added: "Grandstander?"