When US special forces raided the compound of an Islamic State leader in eastern Syria in May, they made sure not to tell the neighbours.
The target of that raid, the first of its kind since US jets returned to the skies over Iraq last August, was an Isis official responsible for oil smuggling, named Abu Sayyaf. He was almost unheard of outside the upper echelons of the terror group, but he was well known to Turkey. From mid-2013, the Tunisian fighter had been responsible for smuggling oil from Syria’s eastern fields, which the group had by then commandeered. Black market oil quickly became the main driver of Isis revenues – and Turkish buyers were its main clients.
As a result, the oil trade between the jihadis and the Turks was held up as evidence of an alliance between the two. It led to protests from Washington and Europe – both already wary of Turkey’s 900-mile border with Syria being used as a gateway by would-be jihadis from around the world.
The estimated $1m-$4m per day in oil revenues that was thought to have flowed into Isis coffers over at least six months from late 2013 helped to transform an ambitious force with limited means into a juggernaut that has been steadily drawing western forces back to the region and increasingly testing state borders.
Across the region, violence has been spreading across borders, scattering huge numbers of refugees and contributing to the turmoil in neighbouring regimes. Few countries – from Turkey to Jordan, Lebanon, Iraq and Israel – remain unscathed by the tide of chaos spreading out from Syria.
Despite one year of air strikes aimed at crippling the group’s spread, Isis remains entrenched in northern and eastern Syria, in control of much of western Iraq and camped on Lebanon’s eastern border. Its offshoots are gathering steam in north Africa and now, more than at any time since the latest incarnation of Isis emerged, its leaders claim to be positioning the group for strikes well outside the territory that it now controls.
In the wake of the raid that killed Abu Sayyaf, suspicions of an undeclared alliance have hardened. One senior western official familiar with the intelligence gathered at the slain leader’s compound said that direct dealings between Turkish officials and ranking Isis members was now “undeniable”.
“There are hundreds of flash drives and documents that were seized there,” the official told the Observer. “They are being analysed at the moment, but the links are already so clear that they could end up having profound policy implications for the relationship between us and Ankara.”