Thousands trapped in Manbij

Tens of thousands of civilians are trapped inside the northern Syrian city of Manbij after US-backed fighters surrounded the Daesh (IS) group stronghold, a monitor said Saturday.

The Syrian Democratic Forces (SDF) encircled Manbij on Friday, severing IS's principal supply route between Turkey and its de facto Syrian capital, Raqa.

The Syrian Observatory for Human Rights, a British-based monitor, said warplanes from a US-led coalition were conducting heavy bombing raids on Manbij.

"Tens of thousands of civilians who are still there can't leave as all the routes out of the city are cut," Observatory head Rami Abdel Rahman told AFP.