Kurds cuts off key supply route to Isis HQ

Isis' main supply route to its Syrian headquarters has been cut after Kurdish forces successfully recaptured a strategic town on the Syrian-Turkish border today.

Forces from the People's Protection Units (YPG), allied with Syrian rebel groups and backed by coalition airstrikes, took full control of the town of Tal Abyad earlier today, killing at least 40 Isis militants and scattering the rest of the Islamist forces, according to UK-based monitor the Syrian Observatory for Human Rights (SOHR).

The town lies less than 100km north of Raqqa, Isis' Syrian stronghold and the capital of their self-declared caliphate, which has been ruled by the militants for more than a year.

The loss of Tal Abyad represents a huge blow to Isis' supply lines and could also limit the number of foreign fighters able to cross from Turkey into Syria to join the militant group.

An estimated 20,000 foreigners, including almost 4,000 Western Europeans, have joined Sunni militant groups, such as Isis, in Syria and Iraq since the outbreak of conflict in 2011 when the Syrian civil war began.

According to Doruk Ergun, research fellow at Istanbul-based foreign policy thinktank Edam, the loss of Tal Abyad will be keenly felt by militants in Raqqa.

"Isis has lost a significant position which it uses to smuggle goods, oil, electricity and also militants and weapons. So it was a clear loss for Isis and a clear win for the Syrian Kurdish forces," says Ergun. "It was the most direct and biggest route to Raqqa."

Ergun adds that Isis now are in control of just one border crossing between Turkey and Syria, at Jarabulus in northern Syria.

Kurdish militants were seen today raising the yellow flag of the YPG in Tal Abyad, known in Kurdish as Girê Sipî.

According to the UNHCR, the Kurdish advance displaced 23,000 people from the town, who fled to Turkey as fighting intensified. Refugees were stranded on the Syrian side of the border over the weekend after Turkey closed the crossing, saying it would only allow them through in the event of a humanitarian emergency.

After refugees were seen cutting through the wire fences, Ankara ordered on Sunday for the border to be reopened.

The Kurdish advance has been met with great suspicion in Turkey. Kurdish forces now have control of pockets of territory along the Turkish border, including the city of Kobani, which the YPG liberated from Isis control at the start of this year.

Turkish president Recep Tayyip Erdoğan has previously called the YPG forces "terrorists" and accused the US-led coalition of bombing Turkmen and Arabs indiscriminately. The YPG is an offshoot of the Kurdistan Workers' Party (PKK), which has been involved in a bloody 30-year insurgency for independence against the Turkish state.

On Monday, 15 Syrian rebel groups also accused the Kurdish forces of a "sectarian and ethnic cleansing campaign".

Ergun says that Ankara finds itself between a rock and a hard place when asked to choose between who it would prefer in control of Tal Abyad - Isis or the YPG.

"It's a double-edged sword for Turkey having the YPG there. The Turkish government doesn't really want Isis to be there, that's the worst case scenario, but there's always this hesitation to have any Kurdish group close to the border because of the YPG's obvious connections to the PKK," he says.

Despite the setback, Isis is still in control of about a third of the territory in Iraq and Syria, including major Iraqi cities such as Mosul and Ramadi.