Beirut: Syrian opposition activists and media say Kurdish-led forces are closing in on the de facto capital of Daesh in Syria, seizing a cotton factory only a couple of miles north of the city.

The Raqqa Campaign, a Facebook page affiliated with the Kurdish-led forces, says the fighters seized the cotton factory, 4 kilometres north of the city on Saturday. Kurdish media also report the factory is captured.

The Britain-based Syrian Observatory for Human Rights says the Kurdish-led Syrian Democratic Forces, backed by air strikes from the US-led coalition, are on a multi-pronged offensive, clashing with militants northeast and northwest of Raqqa.

The Kurdish-led forces said on Friday they expect to advance on Raqqa this summer, following their capture of a strategic town and dam west of the city.