While Turkey-led military operations continue in northern Syria in order to eliminate the PKK/PYD threat along its border, the U.S. support to the terrorist group's armed wing in Syria, YPG has remained to show itself in several ways since more than two years.
PYD is the Syrian offshoot of the PKK -- considered a terrorist group by Turkey, the U.S. and EU -- whereas YPG is the armed wing of PYD, and considered by the U.S. a "reliable partner" in the region in the fight against Daesh.
The Obama administration initially admitted supporting the PYD/YPG at the end of 2014 when Daesh surrounded Ayn Al-Arab, a Syrian city close to the Turkish border.
By claiming that it supported the anti-Daesh fight in Syria including the protection of Ayn Al-Arab from the terrorist group, the U.S. dropped weapons, ammunition and medical supplies to the YPG from the air, senior U.S. administration officials said, according to a Wall Street Journal article dated Oct. 20, 2014.
The American authorities also confirmed that one of the medical aid packages that they dropped fell mistakenly into the hands of Daesh.
Meanwhile, former U.S. ambassador to Iraq, Zalmay Khalilzad, met with PYD's leader Salih Muslim on Dec. 9, 2014 in Erbil, northern Iraq, reportedly to discuss further military coordination over Ayn Al-Arab, according to a story by Erbil-based Rudaw Media Network.
Shortly after the Turkish government approved in July 2015 the use of its southern Incirlik Air Base for the U.S.-led international coalition against Daesh, the tensions between the two NATO allies intensified, especially with regard to U.S. assistance to the YPG in northern Syria -- which Turkey opposes strongly.
Despite opposite claims, photos on social media showing U.S. soldiers with YPG insignia were yet another milestone that further strained the relations between Ankara and Washington.
Turkish Foreign Minister Mevlut Cavusoglu reacted harshly to the photos that emerged during an operation launched last May by Kurdish-led Syrian Democratic Forces to liberate Daesh's self-declared capital of Raqqa, calling the incident "not acceptable".
Asked about the photos and whether the U.S. provided arms to the group, the U.S. authorities insistently declined that the U.S. forces were doing much more than training and advising the YPG.
Pentagon spokesman Peter Cook told reporters in a press briefing on May 27, 2016 that the U.S. troops were most likely just being "supportive of that local force [YPG] in their advice and assist role".
On the other hand, Col. Steve Warren, spokesman for Operation Inherent Resolve in Baghdad told reporters the same day that wearing those patches was "unauthorized and inappropriate," and that "corrective action" had been taken.
However, he added that the American Special Forces had a "long and proud history" of wearing such patches of their allies around the world in order to "connect with those they are training".
The U.S. has long promised that the YPG will leave Manbij once it is liberated from Daesh. However, although the Syrian city near the Turkish border was retaken from Daesh last summer, the YPG is still operating in the city.
The issue has been raised several times at meetings between Cavusoglu and U.S. Secretary of State John Kerry as well as the Turkish Chief of General Staff Hulusi Akar and his American counterpart Joseph Dunford.
The Turkish-led Operation Euphrates Shield, which began last August, aims to improve security, support coalition forces, and eliminate the terror threat along Turkey's border using Free Syrian Army fighters backed by Turkish artillery and jets.
The operation also aims to push the PKK/PYD to the east of the Euphrates River and secure the area -- especially Manbij which is located on the west bank of the river. Manbij is currently controlled by the PYD/PKK.
Outlawed PKK/PYD and its military wing YPG are trying to combine their self-declared cantons in Ayn Al-Arab and Al-Hasakah in northeast along the Turkish border with the one in Afrin, northwest corner of Syria, an idea that Turkey has long opposed.
If PKK/PYD fails to capture the town of Al-Bab -- another critical city which is trying to be liberated -- it will not be able to connect Manbij with Afrin. The Turkish army is currently supporting Free Syrian Army (FSA) fighters in liberating Al-Bab.
Last September, the American flag was hoisted over several buildings belonging to the PKK/YPG in Raqqa's Tal Abyad district (which were recognizable from the Turkish border), according to local sources.
"The U.S. and the Western world protected, funded and trained these [Daesh, PKK] terrorist organizations," in northern Syria and parts of Iraq, security expert Abdullah Agar told Anadolu Agency.
These groups are used as "masks" to serve the U.S. and Western interests in the Middle East, according to Agar.
He added that the U.S. never said it armed the YPG although the group's current "sophisticated" weapons such as tanks or stingers were made in the U.S.
"Instead, they say they armed the 'Democratic Syrian Forces' -- 80 percent of which consists of PKK-guided terrorists. This [wording] is shrewd [of them]," Agar said.