The US has retained a military presence in northeastern and eastern Syria since 2014 after Syria's brutal conflict started in 2011 when anti-government protests turned into a complex war entangling rebels, jihadists and outside forces.
The US forces guarded and transported the stolen Syrian oil to Iraq where they sell it to Iraqi oil companies at a lower price and use the money to support the Kurdish-led, US-backed Syrian Democratic Forces and other opposition armed groups in Syria, said Zhu Weilie, the Honorary Director of the Middle East Studies Institute of the Shanghai International Studies University.