Fighters of the US-backed Syrian Democratic Forces (SDF) confirmed from Raqqa that they had shot the footage showing militants of the self-proclaimed Islamic State (IS; formerly ISIL/ISIS) peacefully leaving Raqqa on their watch.

Thought to have been filmed towards the end of the battle for Raqqa, the footage shows buses and trucks carrying dozens of IS militants from the embattled city, according to one of the fighters.

"This is the footage we shot. We still keep them," said the SDF fighter in late November, holding the mobile phone on which the footage was recorded. "We saw them with our own eyes. I was on shift at the Grain Containers turnabout when IS were leaving. There were many of them, we were not afraid of them," he said.

An investigative report by the BBC in early November alleged a "secret deal" that allowed hundreds of IS fighters to depart embattled Raqqa under the eyes of the SDF in early October, as the fight for the city was drawing to a close in early October.