As a result, the town is being fought over by two western proxies. It is not surprising that Mr Obama wants a ceasefire.

The YPG is a Kurdish army that is the Syrian affiliate of the long-established guerrillas from nearby Turkey, the PKK, a leftist, US- and UK-designated terrorist group.

Despite that designation, the YPG’s strength comes in part from its backing from the United States, which gave it air support in its bitter and eventually successful defence against Isil of the border town of Kobane.

But as the YPG attacks rebel-held areas north of Aleppo it is also fighting the very rebel groups who two years ago drove Isil out of western Syria, and who still face off against it just two miles east of Marea.