I ran into Syrian Kurdish Democratic Union Party leader (PYD) Salih Muslim at a well-protected hotel in a Stockholm suburb. Our previous meeting had taken place some six months ago in Iraqi Kurdistan’s Sulaimaniyah when I had asked him whether it was true that the Americans were encouraging the PYD to operate east of the Euphrates and advance toward Raqqa, despite Turkey’s pressures not to let the Syrian Kurdish forces move to the west of the Euphrates. "Before attacking Raqqa, we must retake strategically located Manbij from Daesh [the Islamic State, or IS] to terminate the logistical support provided by Turkey to the Syrian capital [Raqqa] of the Islamic State,” Muslim responded then. “If Americans are serious about the liberation of Raqqa, they have to support us to cleanse Daesh from Manbij.” 

Raqqa is on the east bank of the Euphrates, but Manbij is to the west of the river, northwest of Raqqa.

Months later, following three months of fighting, Americans provided air support to the Syrian Democratic Front (SDF) forces, which predominantly consist of the Kurdish People’s Protection Units (YPG), although it does have an Arab component. The fall of Manbij to the SDF prompted the Turkish military incursion into Syrian territory. Syrian opposition elements supported by Turkey calling themselves the Free Syrian Army (FSA) moved into Jarablus on the Turkish border and secured a 50-kilometer-wide (31-mile) stretch of land, pushing IS westward to al-Rai.

Recently, Dabiq, a town believed to have an important psychological importance for IS, was also taken by Turkish-supported forces.