According to local reports, the two graves were found in the village of Al-Farhaniyah, which is located about six kilometres away from the town of ‘Ain ‘Issa in the northern region of Al-Raqqa.
The reports said that the first mass grave contained the remains of 15 soldiers, while the other was estimated to have 40.
The Syrian Army said the remains were those of the soldiers of the 17th Reserve Division and 93rd Brigade, who were either captured and executed by ISIS or killed during battle.
The Syrian authorities are now working to conduct DNA testing on the remains of the first 15 bodies that were exhumed.
In July of 2014, the Islamic State began to mass expand across the Al-Raqqa Governorate and other areas east of the Euphrates River.
By August of that year, the Islamic State had reached the Tabaqa Airbase in western Al-Raqqa, where they captured over 200 Syrian Arab Army soldiers at the strategic installation.
Upon capturing these soldiers, mostly from the 17th Division, the Islamic State marched the prisoners through the desert region in rural Al-Raqqa, where they filmed themselves executing the men.