The Syrian authorities have unearthed 115 bodies from a mass grave discovered in Syria's northern province of Raqqa, state news agency SANA reports. (AFP photo)

DAMASCUS, Dec. 30 (Xinhua) -- The Syrian authorities unearthed 115 bodies from a mass grave discovered in Syria's northern province of Raqqa, state news agency SANA reported.

The bodies are of civilians and soldiers killed by the Islamic State (IS) militants, who had been controlling the city before their downfall late this year.

SANA said the IS killed those people in mid-2014 near the town of Dibsi Afnan in the southern countryside of Raqqa and left their bodies out in the open before the locals buried them overnight.

Another mass grave was also discovered, SANA said, adding that work is underway to dig out all the bodies.

The Syrian army captured Dibsi Afnan and other areas in July, before the U.S.-backed Syrian Democratic Forces (SDF) captured the capital city of Raqqa in October.

The IS lost all its strongholds in the eastern province of Deir al-Zour and witnessed a near collapse in 2017.

The Syrian authorities are inspecting the areas once controlled by the IS to unveil more atrocities committed by the terrorist group.