Ankara considers the YPG to be no more than the Syrian counterpart of the Kurdistan Workers' Party (PKK), an armed group which has been waging a bloody insurrection against Turkish authorities for nearly 35 years.
The PKK is outlawed by Turkey, and the YPG is similarly viewed as a "terrorist" organisation by Ankara.
As many as 20,000 Turkish-trained and Turkish-armed Syrian fighters are part of the Turkish offensive against Syrian Kurds, launching a huge ground assault on the YPG, yet the incursion has yet to make huge amounts of progress into the tiny Afrin canton of north-west Syria.
There have been several reports this week of fighters loyal to President Assad arriving in Afrin to reinforce the Kurds against the Turks and Ankara's anti-Assad Syrian allies in the Free Syrian Army.
Aaref Watad, a freelance journalist, embedded with Free Syria Army fighters on the front lines, west of Afrin, and sent us these pictures.
The New ArabComments