According to the Voice of America, 50 bodies have been recovered so far, but the grave could contain up to 200 militants and civilians, said Abdallah Al-Eriane, a senior official with the Raqqa Civil Council.

It was discovered under a soccer pitch near a hospital that IS had used as a strongpoint. Al-Eriane said that "it was apparently the only place available for burials, which were done in haste. The jihadists were holed up in the hospital.”

He added that some bodies were marked with the nom de guerre of the militants, while civilians just had first names, NRT reported.

It is one of several mass graves discovered in recent months in territory formerly held by IS.

Reporter’s code: 50101