Raqqa, Syria (BBN)-Kurdish forces in northern Syria say they have captured a key military base from Islamic State (IS) north of the militants’ self-declared capital of Raqqa.

The Kurdish Popular Protection Units (YPG) were backed by US-led air strikes and other rebel groups, reports BBC.

It comes a week after Kurdish forces seized a Syrian border crossing with Turkey from the jihadists.

The move cut off a major supply route for IS.

A Kurdish forces spokesman said they had complete control of the Liwa (Brigade) 93 base, which is deep in IS-held territory.

Redur Xelil said the YPG was now on the outskirts of Ain Issa, a town only 50km (30 miles) north of Raqqa.

“They [IS] have been defeated,” he said.

The military compound, seized by IS last year, overlooks strategic roads linking Raqqa to other IS outposts in Aleppo province to the west and Hasakah province to the east.

Rami Abdel Rahman, a spokesman for the UK-based activist group the Syrian Observatory for Human Rights, said IS’s lines of defence had been “pushed back to the gates of Raqqa”.

The capture last week of the Tal Abyad border crossing allowed the Kurds to link up other pockets they control along the Turkish border, from Iraq in the east to Kobane in the west.

However, the fighting prompted thousands of civilians to flee to nearby Turkey.

Analysts said Tal Abyad was one of the most important border crossings for IS.

Raqqa is the main seat of power in Syria for the militant group, which has proclaimed a caliphate in the territory it controls in Syria and Iraq.