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.
19 Daesh terrorists neutralized in Syria: Turkish military
As many as 19 Daesh terrorists were killed in the last 24 hours in Syria, as part of Operation Euphrates Shield, which was launched in late August 2016 to sweep the terrorist elements from northern Syria, the Turkish Armed Forces (TAF) said. The operation was conducted in al-Bab, Bzagah and Suflaniyah districts, according to the Turkish military. The TAF also said that 367 terrorist targets were fıred upon by land and 27 terrorist targets were hit by airstrikes, destroying shelters, control plants, weapons storage areas and vehicles.48 Daesh terrorists killed in Syria on Sunday: Turkish Army Operation Euphrates Shield was launched by the TAF to support the Free Syrian on August 24 of 2016 and has been continuing for 140 days. Over a 2,100-square-kilometer area has been cleared from terrorists so far. Since the beginning of the operation, more than 2,821 improvised explosive devices and 43 mines have been destroyed.442 arrested in PKK, FETÖ probe in Turkey: Turkish Ministry
US soldiers wearing YPG patches
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".
48 Daesh terrorists killed in Syria on Sunday: Turkish Army
Turkish-led air and ground operations in Syria killed 48 Daesh terrorists on Sunday while Turkish warplanes destroyed 23 buildings and shelters used by the terrorists, Turkey's armed forces said in a statement on Monday.Turkey launched the 'Euphrates Shield' operation in support of Syrian opposition more than four months ago to drive Daesh from the border and in recent weeks they have been besieging the Daesh-controlled town of al-Bab. 69 Daesh terrorists killed in Syria Turkey reduces smuggling incidents on the Turkish-Syrian border Turkey report reveals FETÖ relations with PKK, Daesh
PYD/YPG existence in Syria's Manbij
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.
Yıldırım says will not allow PYD's fait accompli in Syria
Prime Minister Binali Yıldırım spoke in a joint press conference following his meeting with Masoud Barzani, the president of the Iraqi Kurdish Regional Government (KRG), in his Erbil visit as part of renewing ties with both the Iraqi central and Erbil-centered regional governments.Turkish PM meets with northern Iraqi president Turkey's PM makes official visit to Iraq “Terrorist organizations, not only Daesh but the Kurdistan Workers' Party (PKK) and Fetullah Terrorist Organization (FETÖ) are not just Turkey's issues, but our common problems with Iraq and Syria. We are carrying out an operation to wipe out Daesh elements from our southern borders. Our mutual goal is to completely eradicate the terrorist organization, which is the plague of all humanity," Prime Minister Yıldırım said.Terrorism has no future in Turkey: Turkish PM 'We cannot allow a fait accompli by PYD' Yıldırım also stressed Turkey's fight against the PKK, saying that the terror group's attacks on Turkey from its base in Iraq are unacceptable and his country will do whatever necessary. “PKK terrorists cannot be allowed to harbor in Iraqi's Sinjar region. It is our security issue and common problem with both the regional and central Iraqi governments. Thus, we should act together," he said. He also touched upon the PKK-affiliated Democratic Union Party's (PYD) sinister occupation campaign on Arab populated lands in Syria. In this regard, Yıldırım said that the PYD terrorist organization has uprooted Arabs and peshmerga in northern parts of Syria. However, Turkey cannot let a fait accompli of them who seized those lands. “No matter how they changed their names, we clearly know them and what they are doing. They are the PKK's affiliates. They cannot change their essence by renaming. There is no difference between the PKK, PYD or the People's Protection Units (YPG)," he argued. Struggle against FETÖ Additionally, Yıldırım thanked President Barzani over his support against FETÖ and reiterated Turkey's aim to rid all its elements.Turkey in Iraq's Bashiqa out of necessity: PM Yıldırım Turkey, Iraq cooperation council vows to work for peace Iraq says deal reached over withdrawal of Turkish forces from Bashiqa
US flags on PKK/YPG buildings
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.