Middle East

Turkey v Islamic State v the Kurds: What's going on?

YPG fighters in Syria
Turkey has been alarmed by dramatic gains made by the Kurdish YPG militia in Syria

Turkey has opened up a new front in the fight against Islamic State (IS) militants, by bombing their positions in Syria and permitting US jets to do the same from its territory.

But Turkey has also bombed a Kurdish rebel group that is leading the fight against IS in Syria and Iraq.

Turkey's government says its intervention in the conflict will prove decisive.

Critics say Turkey's strategy - complicated by long-standing problems with its large Kurdish minority - is short-sighted and likely to backfire.

How did Turkey get here?

The superficial story behind the Turkish intervention is clear enough. It starts on 20 July with a suicide attack in Suruc, a Kurdish-dominated town in south-eastern Turkey, near the Syrian border.

A bomber blew himself up at a gathering of left-wing activists, killing 32 people. The attack was apparently ordered by IS. However, Kurdish protesters also blamed the Turkish government for colluding with IS - a charge it denies.

Two days later, Kurdish rebels from the PKK - a banned political party and guerrilla movement - killed two Turkish policemen, accusing them of facilitating the Suruc bombing.

The bombing in Suruc triggered protests across Turkey

Meanwhile, IS fighters clashed with Turkish troops along the Syrian border, killing one of them.

Turkey responded last Friday by arresting hundreds of suspected supporters of IS and the PKK, while its aircraft bombed the groups' positions in Syria and Iraq respectively.

Turkey also revealed that it had struck a deal that would grant the US use of the Incirlik base - potentially speeding up air strikes against IS.

Two Turkish troops were killed in an apparent retaliation by the PKK. The group also indicated it may revive a decades-old armed struggle against Ankara.

The Turkish government says it is ready to fight all the enemies of its national interest. But many observers believe it is particularly interested in one enemy.

The question is: Which one?

The conflict in Syria has sent a wave of refugees across the border into Turkey

Some say Turkey will help the Americans hammer IS, while striking the PKK as a warning - no more. Others say it will go after the Kurds hardest, while doing the bare minimum against IS.

Turkish policy is "to pretend that it is waging a war against IS, while at the same time following up on another goal, which is to destroy the PKK," says Kerem Oktem, a professor at the Centre for Southeast European Studies at the University of Graz in Austria.

What has Turkey been doing until now?

For the underlying narrative behind Turkey's intervention, look to its troubled history with the Kurds.

United by ethnicity and divided by modern borders, the Kurds are a sizeable minority within Turkey, as well as within the neighbouring states of Syria, Iraq and Iran.

In each of these countries, the Kurds have agitated against governments, sometimes for greater rights, sometimes for outright independence.

The PKK is regarded as a terrorist group by Turkey, which accuses it of many civilian deaths

An armed struggle in Turkey was led for many years by the PKK, until it signed up to a ceasefire in 2013.

That truce has been strained by the civil war in Syria, which has strengthened the PKK's armed offshoot there, known as the YPG.

Like its allies in the Gulf, Turkey wants the overthrow of Syrian President Bashar al-Assad. It too has been accused of supporting many of the rebel groups fighting him - though not the YPG.

Turkey has looked on, worried, as the YPG has carved out a proto-state across its southern border - an unwanted beneficiary, in its view, of the fragmentation of Syria.

The other big beneficiary has been IS, whose Syrian territory roughly encircles the areas held by the YPG. Turkey denies the accusation, levelled by many Kurds, that it is using IS to check Kurdish influence.

Turkey has nonetheless served as a highway for foreign fighters eager to join the jihad in Syria. Weapons and funds have also allegedly flowed down the same route.

Until now, Turkey has been reluctant to take a leading role in the US-led campaign against IS. Instead, it has labelled the PKK and IS as terrorists alike, and demanded the creation of a buffer zone - controlled by neither group - deep inside Syrian territory along the Turkish border.

Meanwhile, the YPG has taken the lead in the fight against IS in Syria.

Backed by US bombardment, it defended the border town of Kobane against the militants last year. This year, it has driven the militants from more Syrian towns along the Turkish border, expanding the area under its control - and further upsetting the Turkish government.

Turkey has tightened security along its border but is wary of sending troops into Syria

So what changed for Turkey?

The Washington Post reports that the US and Turkey finally reached agreement on a buffer zone in late July, just as they announced a deal on the use of the Incirlik base. Many analysts believe Turkey was spurred into action by the need to check the YPG's westward advance in Syria.

According to this theory, the Ankara government realised that its approach to IS has been counter-productive. By staying on the sidelines, Turkey had inadvertently allowed the YPG to prosper under the shield of American air strikes.

The buffer zone plan reportedly gives Turkey a starring role in the conflict alongside the US.

Details are still unclear, but the plan is said to envisage driving IS out of northern Syria, through US air strikes. Syrian opposition groups - vetted and supported by Turkey and the US - will fill the vacuum, putting a brake on Kurdish territorial gains.

The deal between Turkey and the US suggests a preference for the old alliances between Nato member states, over the shotgun weddings with armed groups on the Syrian battlefield.

The PKK has its bases in the rugged mountains of northern Iraq

"The American and Turkish position from the beginning of the conflict has not been that different," says Aaron Stein, an expert on Turkey at the Royal United Services Institute, a London-based think tank. "The US is not going to choose the PKK over Ankara - ever."

There are other explanations for Turkey's intervention, besides events in Syria.

Sinan Ulgen, an expert in Turkish foreign policy with Carnegie Europe, a Brussels-based think tank, says Ankara has revised its view of IS as "a useful enemy".

Turkey's policy towards IS has exposed it to criticism from Nato allies, he says. Meanwhile, the Suruc attack has increased public appetite for a crackdown on IS, while highlighting the hazards of tolerating the group.

Domestic political considerations may also play a part. The governing AKP party lost its majority in a recent election, forcing it to look for coalition partners. It lost ground to a pro-Kurdish opposition party, the HDP, which made startling gains by appealing beyond its ethnic base.

Mr Oktem argues that the AKP has set its sights on calling a fresh election in the hope of getting a better result that would allow it to continue in government alone.

Fighting the PKK, he says, is part of a drive to weaken the HDP, whereby the opposition party ends up being tarnished by its association with the Kurdish minority.

The attack in Suruc was one of the deadliest in recent Turkish history

What happens to the Kurds?

It is not clear what will happen to the territory acquired recently by the YPG. But if the buffer zone is enforced, they may withdraw from some areas.

"The Kurds are over-extended - they're not welcome in the areas they're extending into," says Mr Stein.

He compares the YPG's position to that of the Iraqi Kurdish militia, the Peshmerga, which is also fighting IS - but has backed away from holding territory where Kurds are not a major ethnic group.

Moreover, says Mr Stein, the YPG may be reassured by the "de facto US security guarantee" that it has enjoyed since the bombing of Kobane.

Turkey may also try to drive a wedge between the YPG and PKK by adopting a softer approach to the Syrian Kurdish group.

"Turkey is making a differentiation" between the two groups, says Mr Ulgen, on account of the YPG's role in the fight against IS. Turkish air strikes, he says, will mainly target the PKK at its bases in the mountains of northern Iraq.

However, there is no guarantee such a tactic will work. The tightly-knit ranks of the PKK and YPG have little regard for national borders and could well reject any attempt to divide them.

Turkey has arrested suspected jihadists - but there are fears of many more in 'sleeper cells'

What else might go wrong?

As the saying goes, no plan survives first contact with the enemy. It is unclear how IS - or the Syrian government - will respond to an uptick in US air strikes. Nor is it clear if the rebel groups that are meant to stabilise the buffer zone will play ball.

Those groups are dominated by Islamists and jihadists, including the al-Qaeda-allied Jabhat al-Nusra - not exactly the "moderates" the US would like to be bombing on behalf of.

Moreover, if Turkey miscalculates against the Kurds and domestic supporters of IS, it could face a dual uprising.

The country's security forces could end up trying to tamp down a domestic insurgency in order to defend the national interests that they are intervening for abroad.

For now, the Turkish and Kurdish forces that are fighting against Islamic State militants are also poised to fight each other.

The outcome of this multi-faceted contest is uncertain. But the Turkish action underscores what has become an unofficial axiom of the campaign against Islamic State: the US goal of defeating the militants cannot be untangled from the conflicting aims of its allies in the fight.