Syrian Kurdish Peoples Protection Units (YPG) fighters launched an assault on Syria's Mannagh airbase on Wednesday. The base has been held by fighters opposed to the Syrian regime of President Bashar al-Assad since August 2013. The Kurds are being backed in this endeavour by Russian airstrikes.
The Russians are currently helping the Syrian military and allied militias surround opposition-held districts in the northern city of Aleppo and cut them off from the nearby northwestern Syrian frontier with Turkey.
An opposition commander named Maj. Yasser Abdul-Rahim told the Associated Press that his forces may lose the base to the YPG given the intense Russian airstrikes being leveled against them.
The ongoing Russian-Syrian offensive in Aleppo is giving the YPG in the northwestern canton of Afrin a chance to expand and relieve their enclave from attack by Islamists like Jabhat al-Nusra.
Many Syrians fleeing the current ongoing Russian bombardments in Aleppo have also sought sanctuary in that Kurdish area.
Turkey has long opposed Afrin joining up with Syria's other northeastern Kurdish majority areas since the 60 miles which lies between Afrin and Kobani is inhabited by non-Kurdish peoples, primarily Arabs and Turkmen.
Syria's Kurds have remained neutral in the war when it comes to siding with either the opposition or Assad. It has however fought Islamist elements of the opposition, like the aforementioned Nusra, which has sought to either kill or subjugate them.