Trump 'Almost Certainly' Met Anti-ISIS Chief Who Resigned Over Syria, Despite Twitter Claims: Official

Brett McGurk, a State Department official coordinating the international campaign against the Islamic State militant group (ISIS), was "almost certainly" known to President Donald Trump before McGurk resigned over the U.S. withdrawal from Syria, despite the president's claims to the contrary, a former senior defense official has said.

McGurk had served as the special presidential envoy for the global coalition to defeat ISIS since 2015. Though he was appointed by President Barack Obama, his role in the fight against the terror group would have made him a key figure in the Trump administration's policy in Iraq and Syria.

Read More: Trump's Syria withdrawal will create dangerous power vacuum: Anti-ISIS coalition

In an email sent to his staff, obtained by The New York Times, McGurk explained that Trump's decision to withdraw all American forces from Syria "came as a shock and was a complete reversal of policy that was articulated to us."

Trump announced his decision to withdraw via Twitter, incorrectly claiming that ISIS had been defeated.

There were more than 2,000 U.S. troops on the ground in the northwest of the country, supporting America's allies—primarily the Kurdish-led Syrian Democratic Forces—in the ongoing fight against ISIS.

McGurk said the president's comments "left our coalition partners confused and our fighting partners bewildered. I worked this week to help manage some of the fallout but—as many of you heard in my meetings and phone calls—I ultimately concluded that I could not carry out these new instructions and maintain my integrity."

As news of his resignation broke, Trump tweeted, "Brett McGurk, who I do not know, was appointed by President Obama in 2015. Was supposed to leave in February but he just resigned prior to leaving. Grandstander? The Fake News is making such a big deal about this nothing event!"

But one anonymous former senior defense official told The Washington Post, "It's almost certainly true the president has, in fact, met Brett McGurk." The official said it "would be an indictment of the president himself had he not met the individual coordinating the international coalition against the Islamic State."

Derek Chollet, a former U.S. assistant secretary of defense under Obama, told The Post, "George W. Bush and Barack Obama knew and respected Brett and considered him one of their most important advisers," noting "it's very telling that Donald Trump claims to have never heard of him."

Susan E. Rice, Obama's national security adviser and United Nations ambassador, was among those who criticized Trump for his tweet. "Why don't you know the man who has done more than any civilian to degrade ISIS?" she tweeted.

John Brennan, Obama's former homeland security adviser and CIA director, tweeted: "Brett worked extremely hard over many years to ensure the US fulfilled its leadership role in a critically important part of the world. Like [Secretary] Mattis, Brett believes in the principles, values [and] partnerships that define America. Donald Trump does not."

McGurk's was the second high-profile resignation from within the U.S. defense establishment in the past week. After the Syria announcement, Secretary of Defense Jim Mattis also said he would step down citing disagreements with the president on foreign policy.

Donald Trump Oval office White House
President Donald Trump speaking in the Oval Office of the White House on December 21. Win McNamee/Getty Images