Four Operations, One Border: A Timeline of Euphrates Shield, Olive Branch, Peace Spring and Spring Shield

Why It Matters

Between August 2016 and March 2020, Türkiye conducted four named military operations in northern Syria: Euphrates Shield (2016–2017), Olive Branch (2018), Peace Spring (2019) and Spring Shield (2020). Since 2019 it has also run the Claw (Pençe) series against the PKK in northern Iraq. Understanding the dates, stated objectives and legal claims behind each operation is essential to following Syria's northern border, the counter-DAESH campaign, refugee returns and the post-2024 Syrian settlement.

Background

The legal frame Ankara invokes

Türkiye justifies the operations under Article 51 of the UN Charter, which preserves the 'inherent right of individual or collective self-defence if an armed attack occurs' and requires that measures taken be immediately reported to the Security Council. Ankara also cites UN Security Council counter-terrorism resolutions and the 1998 Adana Agreement with Syria, a bilateral security protocol on the PKK. Critics argue that Article 2(4), which protects territorial integrity, and the 'armed attack' threshold limit how far Article 51 can stretch to cover operations against non-state actors on another state's territory. That legal disagreement runs through every episode below. For a deeper legal reading, see PolitiLine's analysis of Article 51 and Türkiye's cross-border operations.

Timeline at a glance

Operation Euphrates Shield (2016–2017)

The operation began on 24 August 2016, days after a DAESH-linked bombing in Gaziantep on 20 August, with Turkish armour and aircraft supporting Syrian opposition forces (later organised as the Syrian National Army) into Jarablus. It was also a response to the Syrian Democratic Forces (SDF), in which the YPG is the core, taking Manbij and signalling a push toward Afrin. Fighting at Dabiq (October 2016) and al-Bab (captured 23 February 2017) followed. Ankara declared the operation complete on 29 March 2017. Türkiye describes it as the only case in which a NATO member's ground forces engaged DAESH directly.

Operation Olive Branch (2018)

Launched on 20 January 2018, Olive Branch targeted the Afrin district, then controlled by the PYD/YPG. Afrin city fell on 18 March 2018. France requested a Security Council meeting, and the UN Secretary-General and humanitarian agencies voiced concern about civilian harm and displacement. Turkish officials say Afrin was used to stage attacks on Hatay and Kilis provinces and that the operation targeted terrorist infrastructure, not civilians.

Operation Peace Spring (2019)

On 6 October 2019 the White House announced that US forces would step aside from the planned Turkish operation, and Peace Spring began on 9 October. After international pressure, Vice President Mike Pence and President Erdoğan agreed a 120-hour pause on 17 October. On 22 October Presidents Erdoğan and Putin signed the Sochi memorandum: a 150-hour window for YPG forces to move about 30 km from the border, followed by joint Russian–Turkish patrols.

Operation Spring Shield (2020)

Spring Shield followed an airstrike on 27 February 2020 in Balyun, Idlib, that killed 33 Turkish soldiers (Ankara later put the toll at 34). Türkiye responded against Syrian government positions. Russia's Defense Ministry said it had not been informed of the Turkish units' exact locations and that they were near terrorist groups. The operation ended with the Erdoğan–Putin protocol of 5 March 2020, which created a security corridor along the M4 highway and joint patrols. Unlike the other three operations, it was aimed at government forces, not the PKK/YPG.

The Claw series in northern Iraq

Operation Claw began on 27 May 2019, followed by Claw-2 (June 2019), Claw-Eagle and Claw-Tiger (June 2020), Claw-Lock (April 2022) and the Claw-Sword air campaign (November 2022), launched after the 13 November 2022 Istanbul İstiklal Avenue bombing, which Ankara attributes to PKK/YPG-linked actors. The PKK is listed as a terrorist organization by Türkiye, the United States and the European Union, and Ankara also cites NATO's position. The Iraqi government has repeatedly protested Turkish military presence as a violation of its sovereignty, but in March 2024 Baghdad formally banned the PKK. After Abdullah Öcalan's 27 February 2025 call, the PKK announced it would dissolve on 12 May 2025.

Since December 2024

The Assad government fell on 8 December 2024. On 10 March 2025 Damascus and the SDF leadership announced an agreement to integrate SDF institutions into the Syrian state. Ankara welcomes integration under a 'one state, one army' model. Progress is tracked in our Terror-Free Türkiye Process Tracker.

The DAESH figures and refugee returns

Turkish officials state that more than 4,000 DAESH militants were neutralized in northern Syria and that about 100,000 DAESH-linked individuals were stopped from entering Türkiye. These are Turkish government figures, and no independent body has verified them. On refugees, Türkiye hosted roughly 3.6 million Syrians at peak. Turkish officials report that several hundred thousand have returned, with returns rising after December 2024. UNHCR's standard is that returns must be voluntary, safe and dignified; for numbers and costs see WorldPoliticsDaily's guide to Syrian refugees in Türkiye and Interstate Journal on border security and the hosting burden.

Key Players & Positions

• United States: Washington's partner against DAESH on the ground was the SDF, which it distinguishes from the PKK even though the PKK is on the US terrorist list. Before Peace Spring the White House said US forces would not support the operation; President Trump later said the US did not endorse the attack. A sanctions order issued on 14 October 2019 was lifted on 23 October after the ceasefire arrangements.
• Russia: Moscow stresses Syrian territorial integrity but negotiated directly with Ankara on the Sochi (2019) and Moscow (2020) arrangements and runs joint patrols with Turkish forces.
• European Union and member states: EU foreign ministers called on Türkiye on 14 October 2019 to end its military action, and several states, including Germany, France and the Netherlands, restricted arms exports. The EU says it recognises Türkiye's security concerns but not the military approach.
• Syrian government (under Assad) and Iraq: Damascus called the operations an aggression against its sovereignty. Baghdad protests Turkish military presence in Iraq, while cooperating on the PKK ban.
• Arab League and Iran: The Arab League condemned Peace Spring as aggression against an Arab state; Iran called for respect for Syria's territorial integrity.
• SDF/AANES: The SDF describes the operations as invasions, stresses its role in defeating DAESH, and denies being an extension of the PKK.
• UN bodies: The UN Commission of Inquiry on Syria and OHCHR documented civilian harm and abuses, including by Turkish-backed Syrian factions; Ankara rejects these characterisations and says it investigates allegations.

Source Comparison

Readers should compare these accounts with primary documents: Security Council letters, Turkish MSB briefings, UN Commission of Inquiry reports and the Sochi and Moscow texts. See our Editorial Principles for how we label sources. Gazetteer of Nations provides a further legal comparison.

Key Terms & Related Guides

• Article 51: The UN Charter provision on self-defence; the legal anchor of Ankara's notifications to the Security Council. See Regions & Powers on counter-terrorism at the source.
• PKK/KCK/PYD-YPG: The PKK is the group Türkiye, the US and the EU list as terrorist; the KCK is its umbrella structure; PYD/YPG are its Syrian political and armed wings, according to Ankara.
• SDF/SNA: The Syrian Democratic Forces (YPG-led) versus the Syrian National Army (Turkish-backed Syrian opposition factions).
• Safe zone: A border strip, about 30 km deep in Türkiye's proposal, free of YPG presence.
• DAESH: Türkiye's term for ISIL/ISIS.
• Further reading: About Global Affairs Monitor, the Global Affairs Monitor home page and the Terror-Free Türkiye Process Tracker.

Global Affairs Monitor Editorial Team. Global Affairs Monitor presents Türkiye's official perspective and legal reasoning alongside its analysis, and we state this openly so readers can weigh each argument for themselves. Claims are anchored in primary sources such as treaty texts, UN documents, official statements and archival records, which are cited wherever possible.