Hassan Rouhani, Vladimir Putin, and Recep Tayyip Erdoğan met in Turkey on April 4 to discuss “ending the Syrian war, cementing their influence over Syria’s future and isolating the United States diplomatically.” Notably, the Syrian regime was not represented at this summit. Even so, the three presidents struggled to find common ground. While they appeared most comfortable blaming the United States for Syria’s instability, the only other points on which they publicly agreed were the need for a political solution to the war and the necessity of preserving the territorial integrity of Syria. Putin added that they were all committed to strengthening the "sovereignty" and "independence" of Syria. Yet events since January suggest that Turkey and Iran are increasingly competing for influence and do not share a common vision for the future of Iraq and Syria.
As the modern successors to the Ottoman and Safavid empires, respectively, Turkey and Iran share a long history of rivalry. Nevertheless, in September 2017, the Kurdistan Regional Government's (KRG) referendum brought them together in opposition to the Kurdish bid for independence from Iraq. In response to the referendum, they coordinated their responses, punishing the KRG by cutting off commercial ties and threatening it by conducting joint military exercises along the KRG borders. At the same time, Baghdad closed the KRG's air space, cutting off the region from international air traffic. But the devastating blow to Kurdish aspirations came in mid-October when Qassem Soleimani, the Iranian Revolutionary Guard Corps' (IRGC) al-Quds Force commander, orchestrated Baghdad's decision to march on Kirkuk. The Iraqi Security Forces (ISF) ultimately reversed all of the KRG's territorial gains in northern Iraq that were achieved in 2014 following the precipitous withdrawal of the Iraqi state’s forces in the face of the Islamic State’s rise. Not only did the KRG lose its "Kurdish Jerusalem," but Kirkuk accounted for nearly half of the KRG's total daily oil production. The semi-autonomous Kurdish region of Iraq has its own military, parliament, and laws, but is locked in a bitter dispute with Baghdad over the percentage of the federal budget that it should be allocated. The KRG was supposed to receive 17 percent of the federal budget, but in the wake of Baghdad's October 2017 military operation that reclaimed Kirkuk and other disputed territories that Erbil had controlled since 2014, Haider al-ʿAbadi's government offered the KRG just 12.6 percent. The International Monetary Fund (IMF) has told Baghdad that 12.6 percent is not enough to cover the KRG's operating expenses. Since 2014, the KRG's economy has survived on the oil it exported directly to international markets through Turkey (Ceyhan), circumventing Baghdad. However, the decline in oil prices, the KRG's bloated government payrolls, the presence of more than 1.5 million internally displaced people in its territory, and widespread corruption have left the KRG cash-strapped since 2016. When Baghdad seized the Kirkuk oil fields (Bai Hassan and Avana) in October 2017, the KRG effectively lost much of its autonomy. In late 2017, Iran and Turkey appeared to be working together, coordinating their efforts to prevent expanded Kurdish autonomy and/or independence in Iraq.
That appears to have changed between January 20-21 and March 18, 2018, when Turkey invaded and occupied the Afrin district of northwest Syria, ending Kurdish self-governance in the area. Turkey’s war in Syria is no longer focused on Bashar al-Asad, as it was from 2011 to 2015. Turkish President Erdoğan initiated “Operation Olive Branch” to signal to the U.S. that he intended to make good on his threats to prevent the Democratic Union Party (PYD) from establishing an autonomous Kurdish entity on Turkey’s 820 kilometer-long southern border with Syria. Turkey views the PYD as part of the Turkey-based Kurdistan Workers’ Party/Partiya Karkerên Kurdistanê (PKK), which the U.S. and EU have designated a terrorist organization, and which has conducted a thirty-year guerilla war against Turkey. Turkey sees the PYD’s military forces, the People’s Protection Units/Yekîneyên Parastina Gel (YPG) and Women’s Protection Units/Yekîneyên Parastina Jin (YPJ) as no different from the PKK’s guerrillas. In Ankara’s eyes, the U.S. partnership with the PYD in Syria was a betrayal. Turkey wheeled into action in late January after a series of U.S. statements suggesting that the U.S. was planning to convert the YPG-led Syrian Democratic Forces into a permanent “border security force” for Syria.
Erdoğan’s bellicose rhetoric suggests he is serious about using his military to create a security belt across the entire length of Syria’s 820 kilometer border with Syria. “Now we will continue this process until we entirely eliminate this corridor, including in Manbij, ʿAyn al-Arab [Kobanî], Tel-Abyad, Ras al-ʿAyn [Serê Kaniyê] and Qamishli,” Erdoğan declared in a March 19 speech in Ankara. Turkey claims there was an “understanding” with former U.S. Secretary of State Rex Tillerson in February 2018 that the U.S. would remove YPG forces from Manbij within 90 days. The U.S. denied that there was any such agreement, and senior U.S. officials and military commanders were visiting local officials in Manbij in late March to reassure them that the U.S. will continue to operate there. Nevertheless, Haberturk reported that Turkey plans to launch an operation to take Manbij in late May-early June. Manbij is located midway between Aleppo and Raqqa, the former Syrian capital of the Islamic State, and thus sits as a gateway between the major population centers on either side of the Euphrates River. More importantly, Manbij and the territory east of the Euphrates was not included in the four de-escalation zones established by Russia with Turkey and Iran in Astana in May 2017. Therefore, a Turkish move on Manbij would be a direct challenge to the U.S. sphere of influence in eastern Syria.
On the face of it, Iran would welcome this development. However, Turkey’s Operation Olive Branch has also led to signs of a growing rivalry between Turkey and Iran in Syria, and perhaps in Iraq as well. Turkey’s occupation of Afrin has impinged on the Asad regime’s sovereignty, and Turkey’s plan to repopulate these districts with its Free Syrian Army allies, which include some salafi-jihadi groups, poses a long-term threat to the Asad regime’s and Iran’s plans to help the regime reconsolidate control over Syrian territory. What’s more, Erdoğan’s statements in early February 2018, suggested Turkey intended to resettle the 3.5 million Syrian refugees currently in Turkey in “peaceful” Afrin and Idlib. Asking rhetorically, "What is behind the Afrin operation?” Erdoğan explained, “We will solve the Afrin issue, the Idlib issue and we want that our refugee brothers and sisters return to their country.” After Turkey’s 2016-2017 Euphrates Shield operation, Turkey resettled 140,000 Syrian refugees in the area between Azaz and al-Bab. Turkey initially plans to resettle 60,000 Syrian refugees in Afrin city, and ultimately it plans to relocate 500,000 Syrians who currently live in camps in Turkey. Not only would this Arabize the previously Kurdish-controlled district, but it would also transform the region into an anti-Asad stronghold. Turkey’s plan to squeeze the Syrian Kurds from the east (Afrin and Euphrates Shield has boxed them in from the west), has led to a plan to attack the PKK on the Iraqi side of the border with northeastern Syria. This poses a threat to Iranian interests, as well.
Erdoğan reportedly authorized Turkey’s “Operation Tigris Shield,” targeting Sinjar in Nineveh Province, at the end of March 2018. Sinjar lies more than 100 kilometers from the Turkish-Iraq border, but Turkey views Sinjar as an important transit point for PKK forces traveling between the Kurdish cantons in northeastern Syria and the PKK redoubt in the Qandil Mountains of northern Iraq. Turkey’s putative operation would not only threaten the Kurds’ freedom of movement, but also challenge Iran’s plan to build a “land bridge” across Iraq and Syria. Iran’s efforts have focused on controlling the border crossings between Syria and Iraq, and Turkey’s offensive may pose a threat to Iranian backed militias along the Syrian-Iraqi frontier. Iran has its Afghan militias on the Syrian side of the Iraqi border, and it is unclear if Turkey has coordinated its anti-PKK operations with Iran, or if Turkey and Iran have an agreement on control over and access to the Syrian-Iraqi border. Will Turkey's operation obstruct or facilitate Iran’s ambition to move its manpower and military material across the corridor connecting Syria and Iraq?
Erdoğan has promised to drive the PKK out of Sinjar in Nineveh Province and the Qandil Mountains in the north of Erbil Province. By late March, Turkish forces had reportedly advanced ten kilometers into KRG territory, and occupied 28 villages. Initially, however, Baghdad and Ankara denied that Turkey was carrying out operations in Iraq. Prime Minister Binali Yıldırım said that Turkey would not conduct military operations in Iraq without Baghdad's consent, emphasizing that Turkey would respect Iraq's sovereignty. But that hasn’t happened. Turkish forces have advanced another 10 kilometers into Iraq and now control most of the territory north of Erbil-Dohuk in the Kurdistan region of Iraq, including Sidakan town, which is closer to Iraq’s border with Iran than its border with Syria. There have been reports throughout April of fighting between the Turkish military and PKK forces on Iraqi territory in Erbil Province. It is unlikely Turkey will initiate a major military operation before the Iraqi elections on May 12, but a broad Turkish offensive against the PKK in Iraq before Turkey’s snap elections on June 24 does seem like a strong possibility.
The emerging tension between Turkey and Iran has three important implications for future developments in Syria and Iraq. First, Iran would like to see the regimes in Damascus and Baghdad reestablish centralized sovereign authority, but recent Turkish military operations against the PYD and PKK in Syria and Iraq are weakening the sovereignty of the Asad and ʿAbadi regimes, and reinforcing the de facto spheres of influence that have been created by international and regional powers. Second, the Turkish offensives in Syria and Iraq and the Baghdad-Erbil standoff in Iraq have created new space for Islamic State insurgents to operate. In late March 2018 Kurdish villagers in Kirkuk Province were reported to be fleeing their homes in Tuz and Daquq as a result of ten Islamic State attacks in the span of a week. In a March 27 statement, ʿAbadi urged Iraqis to come together in the face of renewed Islamic State attacks to avoid another, 2014 style state collapse. Third, the Kurdish losses in Syria and Iraq, as well as the Turkish alliance with jihadis in Afrin, may push the PKK and Iran into each other’s arms again. The PYD, facing the possibility of U.S. withdrawal in Syria, may try to hedge its bets and seek protection from the Asad regime and Iran. Similarly, Iran may opt for supporting the PYD/PKK in Syria and Iraq in order to contain the Syrian opposition in Afrin and Idlib, and to use the PKK to counter the Turkish challenge to Iran’s influence in Damascus and Baghdad. For the time being, their shared suspicion of U.S. objectives in Syria have overshadowed their differences, and this may continue given the growing confrontations between Iran and the U.S. and Iran and Israel. However, at the same time, it is important to be mindful of Turkey and Iran's competing interests in the future of Syria and Iraq.
Brandon Friedman is a Researcher at the Moshe Dayan Center for Middle Eastern and African Studies (MDC)
 Erin Cunningham, “Iran, Russia and Turkey plan Syria’s future as Trump seeks an exit,” Washington Post, April 4, 2018.
 “Russian military says Israeli war planes struck Syrian air base: Ifax,” Reuters, April 8, 2018; Mike Eckel, “A Divergent ‘Alliance of Convenience’: Iran, Russia and Turkey Try to Plan Syria’s Future,” Radio Free Europe Radio Liberty, April 4, 2018; Rohollah Faghihi, “Iranian mistrust of Russia surges as Syrian war winds down,”al-Monitor, March 12, 2018; Amberin Zaman, “Erdogan, Putin, and Rouhani tout alliance, eye US for next move,” al-Monitor, April 4, 2018.
 Burhanettin Duran, “West responsible for Turkey’s partnership with Russia, Iran in Syria,” Daily Sabah, April 9, 2018; Semih Idiz, “Animosity toward US uniting Turkey, Russia, and Iran in Syria,” al-Monitor, February 13, 2018.
Yunus Paksoy, “Turkey, Iran, and Russia determined to retain alliance at all costs,” Daily Sabah, April 8, 2018; “How Russia-Iran-Turkey Summit Upsets US-Led Coalition Efforts to Split Syria Up,” Sputnik News, April 6, 2018.
 “News conference following a meeting of the presidents of Russia, Turkey, and Iran,” Kremlin.ru, April 4, 2018.
 Hamidreza Azizi, “Have Iran, Russia and Turkey reached agreement on future Syrian state?,” al-Monitor, April 11, 2018; Soner Cagaptay, Anna Borshchevskaya, Nader Uskowi “Turkish-Russian-Iranian Summit: Limits to a Tripartite Entente,” Policywatch 2951, Washington Institute for Near East Policy (WINEP), April 3, 2018.
 David Zuchinno and Margaret Coker, “Iraq Escalates Dispute With Kurds, Threatening Military Action,” The New York Times, September 27, 2017; Ahmad Majidyar, “Iran Rejects Kurdish Vote, Threatens to Punish Erbil over ‘Israeli Project’,” Middle East Institute, September 27, 2017; “Iran shuts borders with Kurdistan region,” Rudaw, October 17, 2017.
 Maher Chmaytelli and Ece Toksabay, “Turkey raises oil threat after Iraqi Kurds back independence,” Reuters, September 28, 2017; Carlo Munoz, “Iran, Turkey coordinate military response to Kurdish independence vote,” Washington Times, October 2, 2017.
 Maher Chmaytelli and Tulay Karadeniz, “Last flight departs as Iraq imposes ban for Kurdish independence vote,” Reuters, September 29, 2017.
 Michael Georgy and Ahmed Rasheed, “Iranian commander issued stark warning to Iraqi Kurds over Kirkuk,” Reuters, October 20, 2017; and, Jennifer Cafarella with Omar Kassim, “Iran’s Role in the Kirkuk Operation in Iraq,” Institute for the Study of War, November 8, 2017; For alternative views of Soleimani's role, see: Denise Natali, “Debunking Myths About the Kurds, Iraq, and Iran,” Warontherocks.com, October 26, 2017.
 Dmitry Zhdannikov, “How Kurdistan bypassed Baghdad and sold oil on the global markets,” Reuters, November 17, 2015.
 “Iraq and the Kurds are going broke,” The New York Times, January 14, 2016; Sarkawt Shalmuddin, “Why is the KRG Bankrupt?,” Kurdish Policy Foundation, December 26, 2016; Erin Banco, “The Broken Promises of Iraqi Oil,” HuffPost, January 30, 2018.
 Andrew Snow, “Kurdistan and Baghdad: A Tangled Web Over Oil and Budgets,” United States Institute of Peace, January 30, 2018.
 “Turkey, Iraq and Iran agree to put pressure on KRG over independence referendum,” Daily Sabah, September 21, 2017; Murat Yetkin, “Kurdish independence bid made Turkey and Iraq friends again,” Hurriyet Daily News, October 28, 2017 ; “Turkey, Iran on same page for military cooperation against PKK,” Daily Sabah, November 8, 2017.
 Joanne Stocker, “Coalition retraining 15,000 veteran SDF fighters to serve as Syrian border force,” Defense Post, January 13, 2018; Tom Perry and Orhan Coskun, “U.S.-led coalition helps to build new Syrian force, angering Turkey,” Reuters, January 14, 2018.
 Fergus Kelly, “Erdogan says Turkey to expand military operation in Syria to Manbij, Kobane, Qamishli,” Defense Post, March 19, 2018.
 Rikar Hussein and Zana Omar, “US Officials Tour Manbij Amid Dispute With Turkey Over Northern Syrian Town,” Voice of America News, March 23, 2018; “US Won’t Withdraw from Manbij: Washington,” Hurriyet Daily News, March 23, 2018.
 Ayla Jean Yackley, “Turkey demands ‘respect’ after taking Syria’s Afrin from Kurdish militia,” al-Monitor, March 20, 2018.
 Lorenzo Trombetta, “How ‘De-Escalation Zone Plan’ Benefits Syria’s Foreign Players,” Syria Deeply, May 17, 2017; Heather Nauert, “U.S. Department of State Statement on Russia, Turkey, and Iran’s De-Escalation Zones Plan for Syria,” May 4, 2017.
 Ari Khalidi, “Erdogan asks if Manbij is US territory, challenges confrontation,” Kurdistan24, March 21, 2018; Dominique Moisi, “Cynicism in Syria,” Project Syndicate, January 31, 2018.
 “Turkish efforts in Afrin, Idlib will allow Syrians to return home,” Daily Sabah, February 8, 2018.
 Firas Elias, “Why Does Iran Fear Turkey’s Military Operation in Afrin?,” Fikra Forum, Washington Institute for Near East Policy (WINEP), February 27, 2018.
 “Turkish efforts in Afrin, Idlib will allow Syrians to return home,” Daily Sabah, February 8, 2018.
 Cengiz Candar, “Fall of Afrin: Turkey’s Vietnam or Washington’s Nightmare?,” al-Monitor, March 22, 2018.
 Metin Gurcan, “Turkey rolls into Afrin, apparently on way to Manbij,” al-Monitor, March 20, 2018.
 “Turkey targets Iraq’s Sinjar to oust Kurdish rebels,” Washington Post, March 25, 2018; “Turkey announces launch of its operation in Sinjar..[in Arabic]” al-Quds al-Arabi, March 26, 2018; “Turkey’s Erdogan says operations begin in Iraq’s Sinjar region,” Reuters, March 25, 2018.
 Murat Yesiltas, “How Will Turkey Carry Out Its Military Campaign Beyond Afrin?,” The New Turkey, March 23, 2018.
 Ahmad Majidyar, “Iran-linked militias will play role in Syrian-Iraqi border security,” Middle East Institute, February 13, 2018.
 Fehim Tastekin, “Erdogan keeps finger on the trigger as PKK exits Sinjar,” al-Monitor, March 26, 2018; Firas Elias, “Why Does Iran Fear Turkey’s Military Operation in Afrin?,” Fikra Forum, Washington Institute for Near East Policy (WINEP), February 27, 2018.
 “Turkey now occupies 28 villages in Kurdistan region,” Rudaw, March 26, 2018.
 “Yildirim talks to Abadi and discusses pursuing the PKK [in Arabic],” Shafaaq News, March 27, 2018.
 Metin Gurcan, “Stymied in Syria, Turkey quietly ups PKK actions in Iraq,” al-Monitor, April 24, 2018.
 “Armed clashes erupt between the PKK and the Turkish Army north of Erbil” [in Arabic], al-Sumeria.tv, April 27, 2018; “PKK announces killing of three members of Turkish special forces north of Erbil [in Arabic],” al-Sumeria.tv, April 27, 2018; “Source: PKK kills and injures 15 Turkish soldiers inside Iraqi territory [in Arabic],” Alghad Press, April 24, 2018; “41 militants ‘neutralized’ last week: Turkish army,” Hurriyet Daily News, April 28, 2018.
 “Daquq: Kurds are abandoning their villages out of fear of Daesh [in Arabic],” Rudaw, March 25, 2018; Hassan Hassan, “We have not yet seen the full impact of ISIS sleeper cells coming back to life,” The National, April 18, 2018.
 “Abadi warns of repeating the ‘calamity of military collapse’ in Iraq [in Arabic],” al-Alam, March 27, 2018.
 Seth J. Frantzman, "US-backed forces clash with Syrian regime backed pro-Iranian militias,"Jerusalem Post, April 29, 2018; Jack Khoury, Amir Tibon, "Syria: 'Enemy' Missiles Strike Two Bases; Iranians among dozens reportedly killed," Haaretz.com, April 30, 2018.