Syrian opposition coordination committees have reported that Russian cargo planes airdropped about five tonnes of light weapons and ammunition to the outlawed PKK’s Syrian branch, the PYD, in the Sheikh Maqsoud neighborhood in Aleppo on Tuesday.
There have recently been fierce clashes between Syrian opposition forces and YPG-allied groups in the area where the YPG, the armed wing of PYD, has been fighting with the Ahrar Syria Brigade, which is one of the opposition groups located in northern Aleppo according to various reports.
Turkey's Anadolu Agency reported that Russian-PYD cooperation has increased after Turkey shot down a Russian fighter jet over an airspace violation in northwestern Syria near the Turkish border last week.
The incident has caused a political crisis between the countries which have strong economic ties with one another, leading Turkish and Russian leaders to issue warnings to one another.
Turkey and Russia disagree over how the Syrian civil war should be resolved as Turkey and the US-led coalition against ISIS have consistently called on Assad to step down and backed Syrian opposition groups while Russia and Iran have supported the regime since the beginning of the conflict.
The existing disagreement worsened following the start of high-level Russian military intervention into the Syrian conflict which has been strongly protested by US, Turkey and the NATO alliance. Following the intervention, Russia reportedly increased its political cooperation with the PYD.
The PYD's militant wing the YPG has recently been described by Turkish leaders as a terrorist organisation along with DAESH and the PKK.
Both DAESH and the PKK are recognised as terrorist organisations by Turkey, NATO, the US, and EU.
Turkey has long been confronted with armed attacks in its southeastern regions by the PKK, which was founded in 1974 by Abdullah Ocalan and his supporters in Ankara. Armed clashes and acts of violence have continued on and off for more than 30 years, and claimed more than 40,000 lives.
PYD leaders met Russian top officials in late October in the capital Moscow in order to discuss several issues including opening an official political mission of the party in the country.
Russian ambassador to Turkey Andrey Karlov previously said that the PKK and the PYD are not recognised "as terrorist organisations by neither Russia nor the United Nations Security Council."
Turkey’s Anadolu Agency (AA) reported on Tuesday that the YPG forces have recently been moving in two different directions under strong Russian military cover in the region between Azaz and Jarablus in order to join Afrin with the territories of Kobane and Jazira which are located in northeastern Syria.
According to AA, the PYD has been attacking opposition forces in Azaz and at the same clashing with DAESH groups in Jarablus in order to pass to the west of Euphrates to reach the Azaz-Marea line.
Turkey has previously declared that it will consider any incursion to the west of the Euphrates river in northern Syria along the Turkish border by PYD as a violation of a "red line" which was set by one of its recent National Security Council meetings.