Turkey v Islamic State v the Kurds: What's going on?
Turkey v Syria's Kurds v Islamic State
(7 months later)
Turkey has launched a high-risk offensive against the rebel Kurdistan Workers Party (PKK), while providing the US with an airbase for attacking Islamic State (IS) militants in Syria.
Turkey has renewed its bombardment of Kurdish fighters of the People's Protection Units (YPG) inside Syria, prompting calls for restrain from the UN, US and EU.
A ceasefire with the PKK collapsed last month, after renewed clashes in south-eastern Turkey. In the latest violence, four Turkish police officers and a soldier were killed in Sirnak, part of the Kurdish-majority region.
Ankara says it is retaliating against what is calls provocations by the YPG, but it has long-warned against the YPG making territorial advances in northern Syria near its border.
Meanwhile, US F-16 fighter jets have arrived at Turkey's southern Incirlik airbase to join the fight against IS. US drones have already launched raids on IS from there.
Why is Turkey hostile to Kurdish rebels in Syria ?
Turkey says its war on two fronts 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.
Turkey views the YPG as an extension of the Kurdistan Workers Party (PKK), a Turkish-Kurdish rebel group fighting for autonomy since the 1980s.
How did Turkey get here?
A ceasefire between Turkey and the PKK ended last year and clashes have since claimed hundreds of lives on both sides.
Violence escalated on 20 July, with a suicide attack in Suruc, a Kurdish-dominated town near the Syrian border.
While Turkey is fighting against the PKK on its soil, neighbouring Syrian Kurds continue carving out a self-declared autonomous region known as Rojava, and the YPG has gained the trust of Turkey 's international allies in the fight against so-called Islamic State (IS).
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.
What is the international reaction to Turkey's bombing of Kurds?
Two days later, PKK rebels killed two Turkish policemen, accusing them of facilitating the Suruc bombing.
The PKK is considered a "terrorist" organisation by the EU and the US , but Turkey has failed to convince its Western allies to do the same for the YPG in Syria .
Meanwhile, IS fighters clashed with Turkish troops along the Syrian border, killing one of them.
The US State Department and Pentagon both pressed Turkey to immediately stop shelling the YPG and urged Syrian Kurds not to expand their areas of operation.
Turkey responded by arresting hundreds of suspected supporters of IS and the PKK, while its aircraft bombed the groups' positions in Syria and northern Iraq, respectively.
The EU also called on Turkey to stop shelling Syrian territory and refrain from further complicating the efforts of world powers to halt the hostilities.
By 10 August, more than 1,300 people had been arrested in the crackdown, including leftists of the banned DHKP-C Marxist group.
The UN has urged Turkey to comply with international law in Syria .
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.
How have the Syrian Kurds reacted to Turkey 's bombardment?
The PKK - branded a "terrorist" organisation by Turkey and its Western allies - has been fighting for Kurdish self-determination since 1984. A ceasefire was signed in 2013.
A Syrian Kurdish-led alliance, which also includes Arabs (Syrian Democratic Forces), has been advancing and taking over strategic areas from various armed Islamist groups despite Turkey 's ongoing bombardments.
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 captured areas include Marea near the town of Azaz, which was included in Turkey's earlier plans for a "buffer zone" in northern Syria.
The question is: Which one?
YPG spokesman Redur Khalil has said that the alliance's forces would advance until they "captured Azaz and expelled all the terrorists".
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.
Why do Kurds accuse Turkey of backing IS and al-Qaeda-linked rebels?
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.
Kurds accuse Turkey of using the US-led coalition against IS as a cover to attack the Kurdish PKK in both Turkey and Iraq , and now against the YPG in northern Syria .
In a BBC interview, PKK leader Cemil Bayik went further, accusing Turkey of attacking the PKK in order to "stop the Kurdish advance against [IS]". So Turkey, he said, was actually "protecting IS".
The US and EU consider the YPG as one of their most effective allies in the fight against IS.
Turkey has previously dismissed such Kurdish allegations.
The Kurds say that Turkey 's bombardment of their positions is helping IS to attack Kurdish-held frontline areas in Syria and Iraq .
What has Turkey been doing until now?
IS militants attacked Syrian Kurdish villages south of Kobane a day after Turkey began shelling the YPG.
For the underlying narrative behind Turkey's intervention, look to its troubled history with the Kurds.
The Turkish bombardment has also angered Iraqi Kurds, since IS has increased its attacks against Iraqi Kurdish forces in the Makhmur area near the city of Mosul .
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.
"Turkey shamelessly and openly backs IS and al-Qaeda terrorists against Kurdish freedom fighters," Sadi Pria, a top Iraqi Kurdish official in Irbil, has said.
In each of these countries, the Kurds have agitated against governments, sometimes for greater rights, sometimes for outright independence.
What role does the PKK have in all this?
Turkey's truce with the PKK was undermined by the civil war in Syria, which strengthened the rebels' armed offshoot there, known as the YPG.
Syrian Kurds, including those leading the YPG, share the PKK's aspiration to establish an autonomous democratic confederation, but the YPG denies Turkey's claim that it is an extension of the PKK.
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.
PKK leaders have repeatedly warned of a "total civil war" inside Turkey in retaliation for attacks against Syria 's Kurds.
Turkey has looked on, worried, as the YPG has carved out a proto-state adjacent to its southern border - an unwanted beneficiary, in its view of the fragmentation of Syria.
Meanwhile, the Turkey-PKK battlefield has expanded from guerrilla fighting in the mountains to urban warfare in the heart of Turkey 's predominantly Kurdish cities, including in Diyarbakir .
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.
Where is this heading?
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.
Turkey says it will continue to bombard the Syrian Kurds as long as it feels threatened by them.
Until now, Turkey has been reluctant to take a leading role in the US-led campaign against IS. Instead, it has called for a buffer zone along its border, stretching far inside Syria - a zone which neither IS nor the PKK would control.
The YPG will most probably ignore Turkey 's threats and continue its advances to capture more areas. In July 2015, the group took over the strategic border town of Tal Abyad despite Turkey 's threats not to do so.
Meanwhile, the YPG has taken the lead in the fight against IS in Syria. Backed by US air strikes, the YPG defended the border town of Kobane against IS last year. This year, it has driven the militants from more Syrian border towns.
On the other side of the border an escalation of the Turkey-PKK conflict is highly likely in the form of urban and rural warfare, especially after winter.
So what changed for Turkey?
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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 Incirlik. 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 cautious approach to IS had been counter-productive. By holding back, 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.
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 - would fill the vacuum, putting a brake on Kurdish territorial gains.
"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 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 managed to reach out 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.
What happens to the Kurds?
If the buffer zone is created, the YPG 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 bases in the Iraqi mountains.
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 thwart any attempt at division.
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 helping.
And Turkey's forces could end up trying to tamp down a domestic insurgency in order to make its intervention in Syria succeed.
In a further complication, Turkey is hunting leftist DHKP-C militants, blamed for several shootings and grenade attacks. The DHKP-C claimed one of its militants fired at the US consulate in Istanbul on 10 August.
For now, the Turkish and Kurdish forces that are fighting IS are also fighting each other.
The outcome of this multi-faceted contest is uncertain. But Turkey's actions underscore an unofficial axiom of the campaign against IS: the US goal of defeating the militants cannot be untangled from the conflicting aims of its allies in the fight.
