Kurdish-led forces in Syria seized a town from the Islamic State in Iraq and the Levant (ISIL) on Tuesday after capturing a military base overnight, aided by US-led air strikes in some of the most dramatic gains yet against the militants.
The Kurdish march deep into the heart of ISIL territory follows their capture of a town on the Turkish border last week, reversing the momentum of the militants who had seized major towns in both Syria and Iraq last month.
Forces led by the Kurdish People's Protection Units (YPG) had taken full control of Ain Issa, said YPG spokesman Redur Xelil. The Syrian Observatory for Human Rights, which reports on the war, said ISIL fighters had completely withdrawn from the town.
Overnight, advancing forces including Syrian rebels fighting alongside the YPG took control of the nearby Liwa-93 military base, a strategic objective that ISIL had captured last year from government forces.
The advance to Ain Issa brings the kurdish forces and their allies to just 50 kilometers (30 miles) from Raqqa, ISIL's de facto capital, from which it rules over a "caliphate" across much of Syria and Iraq.
But Xelil said an assault on the city was not currently on the agenda. The Observatory said the aim of the advance was to seize control of an east-west highway running through Ain Issa, which links the city of Aleppo with the northeastern province of Hasaka.
The United States and its Arab and Western allies launched an air campaign against ISIL last year after the fighters, also known as ISIS, ISIL or Daesh, proclaimed their "caliphate" to rule over all Muslims.
The YPG fighters have emerged as the most credible ally of the US-led campaign on the ground in Syria, where Washington has fewer friends than in Iraq. Xelil described the US-led air support as "excellent."
In a separate battle, the Syrian military and militias fighting alongside it have gained ground to the northwest of the city of Palmyra, which ISIL captured from government control last month, according to the Observatory and a source in Syria briefed on the situation.
The West and its Arab allies have shunned the idea of partnering President Bashar al-Assad in the fight against ISIL.
‘Stranglehold'
The group has shown little resistance to the latest YPG-led advance. A Pentagon spokesman said last week that ISIL had appeared to "crack" at Tel Abyad on the Turkish border.
However, a US government source, speaking on condition of anonymity, said the gains were not a sign of ISIL falling apart, but rather reflected how the Kurdish-led forces were making a concerted effort against specific targets.
Xelil said ISIL had been "shocked" by the assault.
The YPG advance gathered pace last week when the Kurds, in partnership with smaller groups under the banner of the Western-backed Free Syrian Army (FSA), captured Tel Abyad and cut an ISIL supply route from Turkey.
Coordination between the YPG and the US-led alliance has deepened since they first joined forces to defend the town of Kobani, also on the Turkish border, defeating ISIL fighters in January after four months of battle there.
Asked whether the de facto ISIL capital was now a target, Xelil said: "Raqqa is a Syrian city, like Tel Abyad and Kobani, and all Syrians want it freed of Daesh terror. But at the current time it is not included in our agenda."
Thousands of people have fled the YPG-led advance into Raqqa city in recent days, the Observatory says.
Some people escaping Tel Abyad have accused the Kurds of expelling Arabs and Turkmen, a claim dismissed as propaganda by the YPG. More than 2,000 Syrians who had fled into Turkey crossed back into Syria on Monday.
The Observatory says there have been no systematic YPG abuses, though some have been carried out by individuals.
Syrians return to Tel Abyad
Hundreds of Syrians who fled the fighting in Tel Abyad continued to cross the Akçakale border gate heading to their homes in the Syrian town on Tuesday.
After four days of closure, the Turkish authorities and the Democratic Union Party (PYD) reopened the border gate. Kurdish officials cited security reasons for not allowing Syrians over the weekend.
The UN Refugee Agency said 23,000 Syrian refugees crossed Turkish border early in June. Even after things began to get quiet in Tel Abyad, the number of Syrians who returned to the town remain modest.
Kurdish forces discover underground ISIL tunnel in Tel Abyad
YPG fighters have uncovered an incomplete underground tunnel 500 meters in length in Tel Abyad after capturing the town from ISIL.
Speaking to Turkish media, Kurdish forces said ISIL began to build a tunnel for protection from air bombardments conducted by the US-led global anti-ISIL coalition.
Supported by US air strikes, the YPG has reclaimed control of the town from ISIL, cutting off a major supply line of the group.
“ISIL aimed to bring goods, ammunition and equipment from Turkey once the tunnel, which is very close to the Turkish border, is completed,” one YPG fighter said.