As US forces strike Syrian militias backed by Tehran, many fear delegation to the Pentagon and the looming defeat of the Islamic State could fuel a fiercer fire
US forces have opened fire on Iranian-backed forces in Syria three times in the past month, amid mounting tensions that observers and former officials worry could easily turn into an unplanned, spiralling conflict.
The three recent incidents took place at al-Tanf, a remote desert outpost near the point where the Syrian, Iraqi and Jordanian borders meet. There, a 150-strong force of US soldiers who are training local fighters to take on the Islamic State (Isis) was approached by convoys of militias fighting for the Assad regime. They responded with air strikes.