Brett McGurk, the outgoing special presidential envoy to the coalition fighting the Islamic State, on Monday wished his colleagues well "as they work under extremely difficult circumstances to protect the interests of our great country."
"Today was my last day at the State Department," he wrote on Twitter. "I wish my former civilian and military colleagues well as they work under extremely difficult circumstances to protect the interests of our great country. It was a privilege to serve alongside them."
McGurk left the administration earlier this month after President Donald Trump announced the withdrawal of U.S. forces from Syria.
In his resignation letter, McGurk said ISIS militants were on the run, but not yet defeated and the premature pullout of U.S. forces would create the conditions that gave rise to IS.
Trump on Twitter lashed out McGurk.
"For all of the sympathizers out there of Brett McGurk, remember, he was the Obama appointee who was responsible for loading up airplanes with 1.8 Billion Dollars in CASH & sending it to Iran as part of the horrific Iran Nuclear Deal (now terminated) approved by Little Bob Corker," Trump tweeted last week, referring to Sen. Bob Corker, R-Tenn., who also condemned the withdrawal.