As Kurdish forces headed to the frontlines to fight the Islamic State of Iraq and Greater Syria (ISIS) this weekend, they came under attack, not by ISIS but by Turkish fighter jets.

“They were going to Kirkuk and Sinjar to fight ISIS,” says Zagros Hiwa, a spokesman for the Kurdish PKK forces. The PKK, The Kurdistan Workers’ Party, is a Kurdish separatist group and also one of the forces fighting ISIS on the ground in Iraq and Syria. They are now also under attack by Turkey.

Last week, the Turkish government announced it was joining the war against ISIS. Since then it has arrested more than 1,000 people in Turkey and carried out waves of air raids in neighboring Syria and Iraq. But most of those arrests and air strikes, say Kurdish leaders, have hit Kurdish and left wing groups, not ISIS.

They say Turkey is now hindering, rather than helping, the fight against ISIS. “Most of our forces that have been targeted were forces that were preparing themselves to go to fight against ISIS,” says Zagros.

Kurds are an ethnic minority that live in parts of Syria, Iraq, Turkey and Iran. They have been persecuted for decades — from Turkey’s suppression of Kurdish identity and banning of Kurdish language to Saddam Hussein’s use of chemical weapons on Kurdish communities. Their leaders, from the numerous different parties and rebel groups that represent them, have long sought an independent Kurdish state encompassing that territory and have fought against their respective governments to try to achieve that.

For decades, Turkey fought the PKK in a guerrilla war to push for sovereignty in Kurdish areas of Turkey, but for the past two years the parties have had a truce and were engaged in a peace process. In recent days, Turkey has arrested hundreds of Kurdish activists and politicians and hit the PKK with more than 450 strikes, according to Kurdish leaders. The Turkish government hasn’t said how may air raids it has carried out or who were the targets.

Hoshang Waziri, a political analyst based in Erbil, says the Kurds’ recent territorial gains in Syria along Turkey’s border and their increasing political legitimacy in the eyes of the West, have made the Kurds a bigger threat to Turkey than ISIS. “The fear of the Turkish state started with the Kurdish defeat of ISIS in Tel Abyad,” says Waziri.

At the beginning of the year, the Syrian side of the border was controlled by a patchwork of different groups — Kurds, ISIS and other rebel factions. However, in the last few months Kurdish forces have pushed west after re-taking the border town of Kobane earlier this year. They have taken a number of key areas along the border and connected the territory they control. Now the YPG, a PKK-affiliated group, which represents Syrian Kurds, has semi-independent rule over contiguous swathes of the border areas.

Much of these territorial gains were achieved with the help of U.S. air strikes.

The success of the Syrian Kurds, with the support of Turkish and Iraqi Kurds has enhanced the Kurd’s international profile and their self confidence. The Kurdish groups are being seen as the most effective ground troops in the battle against ISIS as Turkey sits almost idle with its well-equipped army on the border. Turkey has even been accused of aiding ISIS by allowing them to move freely in border areas and allowing new recruits to join them.

“The image in the West of the Kurds as a reliable ally on the ground is terrifying for Turkey,” says Waziri. “So before it’s too late, Turkey waged its war — not against ISIS, but against the PKK.”

Turkey has been keen to paint ISIS and the PKK with one terrorism brush. “How can you say that this terrorist organization is better because it’s fighting ISIS?” said Turkish Foreign Minister, Mevlut Cavusogl at a press conference in Lisbon on Monday. “They are the same. Terrorists are evil. They all must be eradicated. This is what we want.”

But some see the war against ISIS simply as a cover for an attack on Kurdish groups. Of the more than 1,000 people Turkey has arrested in security sweeps in recent days, 80% are Kurdish, associated either with the PKK or the non-violent Kurdish Peoples’ Democratic Party (HDP), says İbrahim Ayhan, a member of parliament for the HDP. “The victory of the Kurds against ISIS was seen by Turkey has some sort of challenge,” says Ayhan. “This is all seen as a threat by Turkey.”

Ayhan says another threat came from inside Turkey. While Kurds in Syria have gained territory and international recognition, in Turkey, Kurds have gained seats in parliament. In the June elections Recep Tayyip Erdoğan’s Justice and Development Party (AKP) failed to get the majority it sought while the Kurdish HDP increased its representation.

That left Erdoğan and the AKP struggling to form a government. Ayhan says the AKP needs a state of “chaos” to perusade voters that it is the only bulwark against chaos. As of yet no new government has been formed in Turkey and if that doesn’t happen in the next few weeks, new elections will be called. By that time Ayhad fears many of the leaders of his HDP party will be in jail and some even worry the HDP will be outlawed. At the same time, Erdoğan and his AKP hope they will have shown only they can defend Turkey from internal and external threats.

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