A new statement from the Russian ambassador to the United Nations, Vassily Nebenzia, has revealed that the boundaries between Daesh and the People's Protection Units (YPG) are once again fading away in northern Syria as former Daesh terrorists have allegedly joined the ranks of the PKK-affiliated YPG.

The Russian diplomat said late Thursday that the U.S.-backed YPG freed 400 Daesh terrorists last month and 120 others joined the umbrella organization, the Syrian Democratic Forces (SDF), which includes the YPG. The YPG is the armed wing of the Democratic Union Party (PYD), the Syrian affiliate the PKK, a globally recognized terrorist group, and the SDF is the umbrella organization dominated by the YPG.

The ambassador also said the U.S. ignores this problem and he accused it of double standards in the fight against terrorist.

"The fact that such an issue remains virtually unnoticed serves as a testament to a persistent double standard with respect to terrorists," Nebenzia said. "All those who delivered direct or indirect assistance to ISIL, not to mention the fighters themselves, must be held to account," he added, using an alternative acronym for Daesh.

This, however, is not the first deal between the YPG and Daesh in Syria. In late January, Anadolu Agency (AA) reported by citing local sources that the YPG released all Daesh prisoners in Afrin on condition that they fight against the Turkish military and Free Syrian Army (FSA) participating in Ankara's Operation Olive Branch.

Also, the BBC documented in November that the SDF made a secret deal with Daesh for the evacuation of some 4,000 terrorists from Raqqa. The BBC report provided details on the agreement between the SDF and Daesh on Oct. 12 to arrange the escape of thousands of militants, including some of the most notorious, and their families from Raqqa, with 10 trucks loaded with weapons and ammunition.

The report also contained secret footage, interviews with drivers who transported the militants along with some Syrians, including a shopkeeper and a smuggler, who spoke on condition of anonymity. Experts have said the deal poses a grave threat to all countries due to the possible return of foreign fighters to their countries who could carry out attacks.

The PKK and its Syrian affiliate PYD and YPG are both listed as terrorist groups by Turkey, while the U.S. and EU recognize the PKK as a terrorist group, but not the PYD or YPG, despite their acts of terrorism.