On September 15, the Islamic State, previously known as the Islamic State of Iraq and Syria (ISIS), launched a fourth siege on the Syrian city of Kobani (Ayn al-Arab in Arabic), capturing dozens of villages (International Business Times, September 22, 2014). The strategic location of the Kurdish-controlled town threatens the Islamic State’s expansion toward the Turkish border from Raqqa and could possibly threaten the group’s self-declared caliphate in the future.
Most likely, the Islamic State fears cooperation between the West and the Kurds in Syria to destroy the caliphate. These groups could follow the similar model used in Iraq, where Iraqi Kurds are successfully pushing back the Islamic State with Western support. Without this assistance, the Islamic State would be able to threaten Kurdish security. Now that the United States has bombed the Islamic State in Syria and is looking for local partners to fill up the power vacuum, the Syrian Kurds could possibly be an answer for the new U.S. strategy in Syria.
Siege of Kobani
Kobani was the first town to be captured by the People’s Defense Units (Yekîneyên Parastina Gel – YPG), the main Kurdish militia group in Syria on July 19, 2012 in response to possible Free Syrian Army (FSA) incursions in the town (Al-Monitor, March 30). The YPG was created by militants of the Kurdistan Workers Party (Partiya Karkerên Kurdistan – PKK) on a similar basis as the PKK’s armed wing, the People’s Defense Forces (Hêzên Parastina Gel – HPG) that fights NATO-member Turkey. One of the PKK’s political branches in Syria, the Democratic Union Party (Partiya Yekîtiya Demokrat – PYD), dominates the political power vacuum that occurred after Assad’s forces left, while the YPG defends the PYD’s areas of operation. 
Islamist rebel groups and the Islamic State saw the YPG-controlled enclave as a main threat to control the Turkish border and accused the YPG and the PKK of working with the Assad regime after the Syrian government withdrew from the city in July 2012 (Rihab News, August 1, 2013).
The first siege started when the Free Syrian Army (FSA), the first group to fight the Syrian government, which formed in 2011, and other Islamist groups, including the Islamic State, launched an assault on the town in July 2013, in order to break Kurdish attempts to create autonomous enclaves in Syria (Rudaw, August 6, 2013). The second one began in March 2014 and Kobani was besieged from three sides on March 15, 2014, which eventually failed (Al-Monitor, March 30). This was a response to FSA-YPG cooperation against ISIS in March 2014 (Al-Monitor, March 24), after the clashes erupted between the IS and other anti-Assad armed groups in January 2014 (Daily Star [Beirut], January 4). The Islamic State renewed their siege on Kobani for the third time in July 2014, after capturing most of the Sunni areas of Iraq in June with weapons captured from the Iraqi army (Daily Star [Beirut], July 11). This led the PKK leader, Abdullah Ocalan, to call for a full mobilization of all Kurds to protect Kobani (IMC TV, July 10). This request possibly led to clashes between the Turkish army and PKK fighters on July 23, who tried to pass through the Turkish border (Firat News, July 23).
The latest siege on Kobani was launched on September 15, after the Islamic State switched its focus from Iraqi Kurds to Syrian Kurds since Western support for the Iraqi Kurds in early August stopped Islamic State militants from advancing on Erbil, the capital of Iraqi Kurdistan.
The Kurdish Areas: Buffer or Obstacle?
Kobani is important to armed non-state actors in northern Syria for several reasons. First of all, it is centered between the YPG-controlled Kurdish enclaves of Afrin and Hasakah. As a result, the PYD created three canton administrations in Kobani, Afrin and Hasakah. The YPG has expressed ambitions to control the mixed areas in between these enclaves that mostly fall under Islamic State-control such as Manbij, Jarabulus and Tel Ebyad. Breaking the YPG’s control of Kobani would dash any Kurdish hopes of creating a contiguous region (see Terrorism Monitor, May 2). Therefore, the PKK and PYD often have accused Turkey of supporting sieges against the PYD in Kobani to break the back of the Syrian Kurds. The PKK now accuses Turkey of backing the Islamic State offensive against the Kurds in order to create a buffer zone after Turkish diplomats were recently released in Mosul (Kurdistan24, September 22). Turkey has denounced any suggestions it supports the Islamic State as cheap slander (Daily Sabah, September 16).
The second reason the city of Kobani is strategically important is that anti-Islamic State factions could use the Kurdish regions as a buffer zone against the Islamic State. Since March 2014, the YPG and anti-Islamic State rebel factions have cooperated against their joint enemy from Afrin and Kobani while the Islamic State established full control over the Arab areas in the Hasakah province (Al-Monitor, March 27). The YPG and PYD have realized that it is better to work with the FSA and Arab tribes to prevent threats to Kurdish territory.
Most likely these strategic calculations play a big part in the renewed Islamic State offensive against the Kurds in Kobani. The militant organization sees Kurdish Muslims as part of the greater Muslim community (ummah) and they are therefore a target for territorial expansion for the self-declared caliphate. “We do not fight Kurds because they are Kurds. Rather we fight disbelievers among them,” explained Islamic State spokesperson Shaykh Abu Muhammad al-Adnani. 
Kobani was also depicted as a PKK-YPG stronghold and target by the Islamic State in their recent video release “Flames of War.”  “They [PKK] fought with a secularist ideology for the sake of land for a secular state. Strong fighters they were not,” the narrator of the video said, trying to dispel suggestions that the YPG is the most effective force to fight Islamic State jihadists after the PKK played an instrumental role in pushing back Islamic State advances in Iraq (VOA, September 11).
Statements released by Islamic State show that they possibly fear a joint YPG-PKK assault from Kobani on the Islamic State stronghold in Raqqa with direct Western air support or indirect support. The joint FSA-YPG military coordination body formed on September 11, before the latest siege stated that these two groups need international support to fight the Islamic State in order to eliminate them from Syrian territory (Aranews, September 12). This is one of U.S. President Obama’s stated goals and top American General Martin Dempsey has suggested that the United States arming Syrian Kurds was under consideration (AP, September 20). One of the stumbling blocks to this approach is Turkey, which considers the Kurdish autonomy in Syria a threat and has announced its intentions to form a buffer zone along its border (Hurriyet, September 16).
It is possible that in the future, the West will pressure Turkey to support an FSA-YPG buffer zone if the PYD decides to join the Syrian Coalition. The threat of the YPG to Islamic State territory is most likely the main reason for the Islamic State renewing its attacks on Syrian Kurds.
Moreover, the coalition already called for U.S. airstrikes to help the opposition protect civilians from Islamic State actions, indicating a possible policy change from the Syrian opposition that had previously accused the PYD of working with the Syrian government (Qorvis.com, September 20). “The PYD wants to be part of the international coalition against the IS [Islamic State],” PYD leader Salih Muslim said recently, though the PYD was against any U.S. intervention in Syria in 2013 (Rojavareport, September 4, 2013). 
Even if Turkey blocks the PYD from joining the coalition against the Islamic State, the United States could indirectly support the PYD-FSA alliance by bombing the Islamic State, which would break the jihadist group’s advances and lead to expansion of FSA-YPG territory. This might result in a huge threat to the Islamic State stronghold of Raqqa, considering how close the Kurds are to that city. However, currently it still looks like the Islamic State is continuing its siege since the group’s positions around Kobani have not been targeted yet by external airstrikes. “Although the bases of the ISIL [Islamic State of Iraq and the Levant – another former name for the Islamic State] and all [their] heavy weapons, vehicles and [equipment] are in open air and visible to everyone… They haven’t [been] targeted by the airstrikes,” said YPG-spokesperson Redur Xelil.  It is, therefore, most likely that the Islamic State wanted to prevent a Kurdish threat to areas the group controls by launching a renewed assault against Kobani.
Wladimir van Wilgenburg is a political analyst specializing in issues concerning Iraq, Iran, Syria and Turkey with a particular focus on Kurdish politics.
1. For an in-depth look at the various Kurdish groups, please see Terrorism Monitor, December 13, 2013, https://www.jamestown.org/single/?tx_ttnews%5Bswords%5D=8fd5893941d69d0be3f378576261ae3e&tx_ttnews%5Bany_of_the_words%5D=Kobani&tx_ttnews%5Btt_news%5D=42303&tx_ttnews%5BbackPid%5D=7&cHash=8b5074e97b89061c4e185587bebb1ec7#.VCWSuCmSxuA.
2. Statement by Shaykh Abu Muhammad al-Adnani, September 21, 2014, https://ia601400.us.archive.org/34/items/mir225/English_Translation.pdf.
3. “Flames of War,” Islamic State video, September 19, 2014, https://world.al-mustaqbal.net/flames-of-war-video-transcript/#.
4. Author’s interview with PYD-leader Salih Muslim, September 19, 2014, Brussels.
5. Press Statement by YPG spokesperson Redur Xelil, September 25, 2014, https://www.facebook.com/Redurxelil/posts/586100361495371.