President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE's special envoy to the fight against the Islamic State in Iraq and Syria (ISIS) submitted his resignation on Friday due to his disagreement with the president's decision to withdraw U.S. troops from Syria, according to multiple reports Saturday.

Brett McGurk, the special presidential envoy for the Global Coalition to Defeat ISIS at the State Department, was reportedly planning to the leave the administration in February, but accelerated his departure over Trump's plans to withdraw troops from Syria, sources told CBS News and NBC News.

McGurk told Secretary of State Mike Pompeo Michael (Mike) Richard PompeoTreasury sanctions individuals, groups tied to Russian malign influence activities Navalny released from hospital after suspected poisoning Overnight Defense: Pentagon redirects pandemic funding to defense contractors | US planning for full Afghanistan withdrawal by May | Anti-Trump GOP group puts ads in military papers MORE of his decision late Friday, sources told the networks. He is expect to resign on Dec. 31.

ADVERTISEMENT

The presidential envoy submitted his resignation one day after Defense Secretary James Mattis James Norman MattisBiden courts veterans amid fallout from Trump military controversies Trump says he wanted to take out Syria's Assad but Mattis opposed it Gary Cohn: 'I haven't made up my mind' on vote for president in November MORE announced his own resignation from Trump's Cabinet.

Mattis, who is slated to leave his post at the end of February, said in his resignation letter Thursday that he was stepping down over fundamental differences with Trump's views.

Mattis announced his resignation after he reportedly was unable to get Trump to change his mind on his Syria strategy. His resignation letter was filled with implicit criticism of the president's treatment of U.S. allies.

Trump's surprise decision this week to withdraw all 2,000 U.S. troops currently in Syria was met with opposition by Pentagon officials and members of the foreign policy establishment.

Days earlier, McGurk told reporters that he thought it would be "reckless" to pull the U.S. out of the region amid its ongoing fight with ISIS.

“I think it's fair to say Americans will remain on the ground after the physical defeat of the caliphate, until we have the pieces in place to ensure that that defeat is enduring," McGurk told reporters at the State Department at the time.

"It would be reckless if we were just to say, well, the physical caliphate is defeated, so we can just leave now. I think anyone who's looked at a conflict like this would agree with that," he said.

McGurk, an Obama appointee, had led U.S. efforts to combat the influence of ISIS in Syria, Iraq and Afghanistan since 2015.

The State Department declined to comment on the matter to The Hill on Saturday, citing a "lapse in appropriations" due to the partial government shutdown that started at midnight.

"Communications with the media will be limited to events and issues involving the safety of human life or the protection of property, or those determined to be essential to national security," a State Department spokesperson said.

The government entered a partial shutdown at midnight Friday after Congress was unable to reach a spending deal because it lacked Trump's demands for border wall funding.

The shutdown, which affects about 25 percent of the federal government, is the third shutdown in the past year.

— Updated 2:23 p.m.