child in Aleppo
A girl plays near rubble of damaged buildings in al-Rai town, northern Aleppo countryside, Syria December 25, 2016 Reuters

Mass graves and evidence of war crimes have been found in the recently recaptured Syrian city of Aleppo, Russian military officials have said.

At the height of their powers, militants from western-backed groups such as Fatah Halab (Conquest of Aleppo), the Free Syrian Army and the al-Qaeda-linked Jabhat Fateh al-Sham controlled up to half of the city to the east, but have since been driven out by a Russian-backed bombing campaign.

As soldiers from the Syrian Arab Army (SAA) regained control of the land and coordinated evacuations, evidence of the atrocities were found, the officials said.

"Mass burial sites of dozens of Syrians who had been tortured and massacred have been found," Russian Defense Ministry spokesman Major General Igor Konashenkov told TASS reporters on Monday (26 December).

"Many of them lack body parts, most were shot in the head."

He added: "First results of examinations of Aleppo's districts that were liberated from the so-called opposition are literally shocking."

The claims come as the United Nations General Assembly voted on Wednesday (21 December) to establish a body that will investigate potential war crimes and human rights abuses during the conflict in Syria.

Russia will carefully document its findings and make them fully available to the public for further examination, Konashenkov said.

It was hoped such a move "will bust a lot of myths Western politicians have been feeding the world community with for several years", he said.

He added that in addition to the discovery of several ammunition depots, militants have planted a number of mines in the east of the city.

Konashenkov said: "Over the days preceding liberation, 'moderate oppositionists' were taking active efforts to 'prepare' the territory, planting mines virtually everywhere: streets, entryways to houses, cars, motorbikes and even children's toys."