Thomas Barrack, who President Donald Trump named special envoy last month shortly after he unexpectedly lifted US sanctions on Syria, and who is also US ambassador to Turkey, raised the American flag over the Ambassador's residence in Damascus last week for the first time since 2012.

The US military has about 2,000 troops in Syria, mostly in the northeast. They are working with local forces to prevent a resurgence of the Islamic State, which in 2014 seized large swathes of Iraq and Syria but was later pushed back.