Photo: AFP

A US-backed alliance of Syrian Kurdish and Arab fighters has begun a campaign to expel Islamic State (IS) militants from land north of Raqqa, the BBC reports.

The Syrian Democratic Forces (SDF) is believed to have deployed about 30,000 fighters.

US-led coalition warplanes will support the offensive and Russia has also given its backing.

The SDF did not mention any plan to take Raqqa, the de facto capital of the “caliphate” proclaimed by IS in 2014.