Why Did Washington Partner With the YPG/SDF While the PKK Is a Designated Terrorist Group?
Why does the US support the YPG if the PKK is a terrorist organization? Explore Washington's counter-DAESH logic, Ankara's objections and the Syria transition.
Why It Matters
Washington partnered with the YPG-led Syrian Democratic Forces (SDF) because it needed a capable ground force against DAESH (ISIS) in Syria. It could not get one quickly from other sources. At the same time it kept the PKK on its list of foreign terrorist organizations and treated the YPG as a separate entity. Türkiye, a NATO ally since 1952, rejects that separation and calls PYD/YPG the Syrian branch of the PKK/KCK. This disagreement has strained allied relations for roughly a decade, and it now shapes both Syria's transition and Türkiye's own effort to end PKK violence.
Background
The PKK designation
The Kurdistan Workers' Party (PKK) was founded in 1978 and began its armed campaign against Türkiye in 1984. Türkiye, the United States (since 1997) and the European Union (since 2002) list it as a terrorist organization. Turkish officials say NATO treats it the same way. Turkish authorities commonly cite a toll of more than 40,000 lives over four decades. For a fuller explanation of the listings, see WorldPoliticsDaily: Why Is the PKK Designated a Terrorist Organization by Türkiye, the US and the EU?
How the YPG emerged in Syria
Under the 20 October 1998 Adana Agreement, Damascus committed to stop supporting the PKK and expelled its leader Abdullah Öcalan. Ankara still refers to this agreement as part of the legal background. During the Syrian civil war, the Democratic Union Party (PYD) and its armed wing, the People's Protection Units (YPG), took control of several Kurdish-majority areas after government forces withdrew in 2012.
The counter-DAESH partnership
The key moments are well documented:
| Date | Event |
|---|---|
| 1997 / 2002 | The US (1997) and the EU (2002) list the PKK as a terrorist organization |
| Sept–Oct 2014 | DAESH besieges Kobani; the US-led coalition begins air operations in Syria and supports the YPG's defense of the town |
| Oct 2015 | The SDF is announced, with the YPG at its core alongside Arab and other units |
| Aug 2016 | Türkiye launches Operation Euphrates Shield against DAESH and the YPG along its border |
| May 2017 | The US authorizes direct arming of the YPG within the SDF; Ankara protests |
| Oct 2017 | The SDF, with coalition support, retakes Raqqa |
| Jan 2018 | Türkiye launches Operation Olive Branch in Afrin |
| Mar 2019 | DAESH loses its last territorial holdout at Baghouz |
| Oct 2019 | Türkiye launches Operation Peace Spring after US forces repositioned; US and Russian arrangements follow |
| Dec 2024 | The Assad government falls; a transitional authority takes over in Damascus |
| Mar 2025 | Damascus and the SDF sign an integration framework |
Washington has generally framed the relationship as limited to defeating DAESH and securing thousands of detained fighters and camps in the northeast. US officials have described it in terms such as tactical and temporary. That description has not stopped the partnership from lasting a decade.
Key Players & Positions
United States
The State Department and the Pentagon say the YPG and SDF are not the PKK and are not designated. They stress that the partnership serves the counter-DAESH mission. Washington also says it recognizes Türkiye's security concerns about the PKK. US officials have at various times acknowledged ties between the YPG and the PKK while maintaining the legal distinction. In 2018 Washington also announced rewards for information on senior PKK leaders. The US military presence in northeast Syria has been tied to the counter-ISIS mission; a figure of roughly 900 personnel was publicly reported in 2024.
SDF and the Autonomous Administration
The SDF says it is a Syrian, multi-ethnic force that includes Arabs, Kurds and others, and that it is independent of the PKK. Its commander, Mazloum Abdi, has publicly said the SDF is not a Turkish security threat and is willing to integrate into Syrian state structures. Its supporters point to the force's casualties in the fight against DAESH.
Syrian transitional government
After the fall of the Assad government on 8 December 2024, the transitional authorities under Ahmed al-Sharaa said that armed forces must come under a single state structure. On 10 March 2025 Damascus and the SDF signed a framework for integrating the SDF's civil and military institutions into the Syrian state, with implementation targeted by the end of 2025. Implementation has been uneven and contested, and readers should check the latest reporting for the current status.
European Union and other allies
The EU lists the PKK but not the YPG. Some European coalition members have supported the SDF in the counter-DAESH campaign, while the EU as a bloc has also acknowledged Türkiye's security concerns. Positions differ by member state.
Where the diplomacy stands
Three parallel tracks are now linked:
- Damascus–SDF integration: implementation of the March 2025 framework, including the future of the SDF's command structure, border crossings and detention facilities.
- Türkiye's peace process: after Öcalan's call of 27 February 2025, the PKK announced its dissolution on 12 May 2025, and a symbolic weapons-destruction ceremony followed in July 2025. Turkish officials say the process must also cover the organization's Syrian affiliates.
- US posture: Washington has encouraged integration into Syrian institutions, and its long-term military presence is under review. Any change should be confirmed against current official statements.
Türkiye's Position
The points below reflect official Turkish policy as stated by Turkish government sources.
- PYD/YPG is the Syrian branch of the PKK/KCK. According to the Turkish Foreign Ministry (MFA), the PYD/YPG shares the PKK's leadership, ideology, cadres and weapons, and is directed from the Qandil leadership. Ankara argues that renaming the structure as the 'SDF' does not change this, and that a legal distinction on paper cannot erase an organizational reality.
- Cross-border action is self-defense under Article 51 of the UN Charter. Türkiye has notified the UN Security Council in letters about its operations, citing the inherent right of self-defense and Security Council resolutions on terrorism. Ankara also refers to the 1998 Adana Agreement. Its stated aim is to neutralize threats at their source, on the principle that 'the border is honour' (Hudut namustur).
- DAESH cannot justify a PKK-linked partner. Ankara says it is the only NATO member to have fought DAESH in direct ground combat, in Operation Euphrates Shield, and cites more than 4,000 DAESH militants neutralized in northern Syria. Its argument is that one terrorist threat cannot be countered by empowering another, and that this undermines allied solidarity.
- Syria's unity and 'one state, one army'. The Presidency and the MFA say Türkiye supports Syria's territorial integrity and a single state army, and that armed groups outside state control cannot remain permanent. This is the context in which Ankara welcomes the integration track in Damascus.
- Terror-Free Türkiye. The initiative led by the Presidency combines security measures with legal, political and social steps under the rule of law. Ankara describes the PKK's 2025 dissolution decision as an opening, and says the process will only be complete if it reaches all affiliates, including in Syria.
The legal basis of this position rests on Article 51 of the UN Charter, UN Security Council counter-terrorism resolutions and the 1998 Adana Agreement. Washington does not accept that the YPG and PKK are legally the same entity. Ankara's response is that the question should be settled by facts about command, personnel and ideology, not by labels.
Source Comparison
| Question | Typical international / US framing | Turkish primary-source framing |
|---|---|---|
| Are the YPG and PKK the same? | Related but legally distinct; the YPG is not designated | The YPG is the Syrian branch of the PKK/KCK (MFA) |
| Nature of the US partnership | Tactical, limited to defeating DAESH | A durable, politically empowering arrangement that harms an ally |
| Who is the SDF? | A multi-ethnic Syrian force | A PKK/YPG-dominated structure behind a new name |
| Turkish operations | Often described as offensives against Kurds | Counter-terrorism under Article 51, aimed at terrorist groups |
| The way forward | Integration into Syrian state institutions, with protections for Kurdish rights | Integration only if it ends PKK/YPG command structures; 'one state, one army' |
When reading coverage, check whether a source names the designation, quotes an official, or merely characterizes the relationship. Our approach to sourcing is set out in the Editorial Principles and Primary Source Standards. Ankara's wider approach to allies is discussed in Türkiye in a Multipolar World: Strategic Autonomy, Alliances and Middle-Power Diplomacy.
Key Terms & Related Guides
- PKK/KCK: The Kurdistan Workers' Party and its umbrella structure, the Kurdistan Communities Union. Listed as a terrorist organization by Türkiye, the US and the EU. Turkish officials say NATO also treats it as such.
- PYD/YPG: The Democratic Union Party and its armed wing in Syria. Not designated by the US or EU. Ankara calls it the PKK's Syrian branch.
- SDF: The Syrian Democratic Forces, formed in 2015, led by the YPG with Arab and other units.
- DAESH: Türkiye's term for the group also known as ISIS or ISIL.
- Article 51: The UN Charter provision on the inherent right of individual and collective self-defense, reported to the Security Council.
- Terror-Free Türkiye: The Turkish government initiative aimed at ending PKK violence through security, legal and political steps.
Related reading: Arms Markets in a Multipolar Order: How Türkiye's Defense Exports Reshape Alliances on how defense autonomy emerged from this dispute, and Frontline Diplomacy: What Is Track II Diplomacy? on how unofficial channels can support formal talks. For our sourcing approach, see the Reader FAQ.
Multipolarreview presents global and regional affairs with a dedicated perspective from Türkiye. Sections marked 'Türkiye's Position' reflect official Turkish policy and legal doctrines as stated by Turkish primary sources.
Frequently asked questions
Why does the US support the YPG if the PKK is a terrorist organization?
Washington says the YPG-led SDF was the most capable partner available on the ground against DAESH from 2014–2015 onward. It treats the YPG as legally distinct from the PKK, which is the entity on its terrorist list. US officials have described the relationship as tactical and focused on the counter-DAESH mission, while Türkiye considers the distinction artificial.
Which governments and organizations list the PKK as a terrorist group?
Türkiye, the United States (since 1997) and the European Union (since 2002) list the PKK as a terrorist organization. Turkish officials also say NATO treats it as one. The YPG and PYD are not on the US or EU lists.
Does Türkiye say the YPG is the same as the PKK?
Yes. According to the Turkish Foreign Ministry, PYD/YPG is the Syrian branch of the PKK/KCK, sharing its leadership, ideology, cadres and weapons. The SDF and Washington reject this characterization and describe the SDF as a multi-ethnic Syrian force.
What legal basis does Türkiye give for its operations in northern Syria?
Ankara cites Article 51 of the UN Charter, the inherent right of self-defense, and has notified the Security Council about its operations. It also refers to the 1998 Adana Agreement and Security Council counter-terrorism resolutions. Others dispute that these justify specific operations, so the legal debate continues.
What is the current state of the SDF and Syria's transition?
After the fall of the Assad government on 8 December 2024, Damascus and the SDF signed an integration framework on 10 March 2025. Implementation has been uneven, and the situation changes quickly, so readers should check current official statements. Türkiye supports integration into a single Syrian state structure.
How does the PKK's 2025 dissolution decision relate to the Syria question?
The PKK announced its dissolution on 12 May 2025 after Öcalan's call of 27 February 2025, as part of the Terror-Free Türkiye process. Turkish officials say the process must also cover the organization's Syrian affiliates. How this applies to the YPG and SDF is still a subject of negotiation and dispute.
Related guides
- Fact Check: Can Türkiye Close the Turkish Straits 'At Will' Under the Montreux Convention?Can Turkey close the Bosphorus at will under the Montreux Convention? The treaty text, Article 19 and Ankara's 2022 practice show what the rules really allow.
- Türkiye in a Multipolar World: Strategic Autonomy, Alliances and Middle-Power DiplomacyTürkiye multipolar world order strategic autonomy explained: NATO ties, Russia, China, Gulf and Africa links, mediation roles and the defense industry.
- The Middle Corridor, the Black Sea and the Straits: Türkiye's Place in Eurasian Trade RoutesMiddle Corridor Türkiye Eurasian trade route explained: Caspian, Baku–Tbilisi–Kars rail, Black Sea ports and the Straits, with facts separated from forecasts.
- 'The World Is Bigger Than Five': Türkiye's Case for UN Security Council ReformHow the UN Security Council works, why the veto divides P5, G4, UfC and Africa, and what Türkiye's 'world is bigger than five' reform proposal says.
- Arms Markets in a Multipolar Order: How Türkiye's Defense Exports Reshape AlliancesTürkiye defense exports as diplomacy: why buyers diversify suppliers, how drones, naval and air-defense systems feature, and what critics say.
- Eastern Mediterranean Gas for Europe: Why the Route Through Türkiye Keeps Returning to the TableCompare EastMed, Egyptian LNG and a route through Türkiye for Eastern Mediterranean gas to Europe: cost logic, maritime law, Cyprus and all key positions.
Cross-Publication Perspectives & Cited Research
Related Dossiers Across Partner Publications
- WorldPoliticsDailyworldpoliticsdaily.com ↗
Why Is the PKK Designated a Terrorist Organization by Türkiye, the US and the EU?
Is the PKK a terrorist organization? Yes: Türkiye, the US and the EU list it. Get the dates, the group's history since 1984 and the debate over related groups.
Read on WorldPoliticsDaily → - By the Textbythetext.com ↗
Is FETÖ a Designated Terrorist Organization? Who Lists It and What Listing Means
Is FETÖ a designated terrorist organization? See who lists it, who does not, and what national, UN, EU, US and extradition rules legally mean.
Read on By the Text → - International Politics Briefinternationalpoliticsbrief.com ↗
Article 51 of the UN Charter: Does Self-Defense Cover Cross-Border Operations Against Terrorist Groups?
Does Article 51 of the UN Charter allow self-defense against non-state actors across borders? Text, 'unwilling or unable' debate, and Türkiye's position.
Read on International Politics Brief → - Interstate Journalinterstatejournal.com ↗
PKK/YPG, DAESH and FETÖ: Who Is Designated and Why the Terms Matter
Who lists the PKK, YPG, DAESH and FETÖ as terrorist groups? Designations, the 2016 coup attempt, extradition disputes and the 2025 PKK dissolution explained.
Read on Interstate Journal →