Syrian Kurds, on the offensive, push deeper into Islamic State territory

Kurdish-led forces advanced on Monday deep into territory in Syria held by Islamic State, showing new momentum after they unexpectedly swiftly seized a border crossing from the jihadists last week.
The Kurds, aided by US-led air strikes and smaller Syrian rebel groups, have pushed to within 7 km (4 miles) of Ain Issa, a town 50 km (30 miles) north of Islamic State's de facto capital Raqqa city, said Redur Xelil, spokesman for the Kurdish forces. The rapid advance into Raqqa province has defied expectations of a protracted battle between the Kurdish YPG group and Islamic State fighters, who waged a four-month battle for the border town of Kobani, where the Kurds finally defeated the jihadists in January.
Raqqa is the main seat of power in Syria for Islamic State, the group also known as ISIS or ISIL, which has proclaimed a caliphate to rule over all Muslims from territory it controls in both Syria and Iraq.
The United States has been leading an air campaign against the group in both countries since last year. The Kurds have been the most important partner so far for the US-led campaign in Syria, where Washington has far fewer allies on the ground than in Iraq. The Kurdish front in northern Syria has been one of the few sources of good news for the global campaign against Islamic State since the jihadists made major advances last month in western Iraq and central Syria.
A spokesman for the Pentagon said last week Islamic State forces had appeared to "crack" at the Turkish border town of Tel Abyad, which fell to the YPG in less than two days, cutting Islamic State's supply route from Turkey. The YPG-led forces were now battling Islamic State on the outskirts of a military base to the south-west of Ain Issa, according to the Syrian Observatory for Human Rights, which monitors the conflict.
Islamic State has held the base, "Liwa 93", since capturing it from the Syrian military last year. If the Kurds take it, that would mean Ain Issa had effectively fallen, the observatory said. Thousands of people had fled from Ain Issa towards Raqqa city in the last two days, it added.
Some refugees from the Tel Abyad area had accused the YPG of driving Arabs and Turkmen from territory seized from Islamic State. More than 23,000 people had fled northern Syria into Turkey this month, escaping the fighting. With the fighting having moved on and a border crossing reopening, some of the refugees were returning to Tel Abyad on Monday. Hundreds of Syrians, mostly women and children carrying bags of belongings, returned across the border from the Turkish town of Akcakale.