US-backed forces said on Tuesday that they had captured Raqa's state hospital where some of the last Islamic State group fighters had been holding out in their onetime Syrian bastion.

"The national hospital was liberated and... 22 foreign mercenaries were killed," the Syrian Democratic Forces said. "Clashes continue with great intensity near the municipal stadium."

The advance came a day after the SDF took an infamous roundabout used by the jihadists for public beheadings and crucifixions in Raqa