Turkey sent ground troops into northern Syria in August to assist Syrian opposition forces in clearing a border area of IS militants and to prevent Syrian Kurds from making greater territorial advances.
Ministry spokesman Maj. Gen. Igor Konashenkov said in an emailed statement on Monday that the Russians found "found mass graves of several dozens of Syrians who suffered atrocious torture and massacre."
Konashenkov also criticized the opposition rebels, who controlled eastern Aleppo before they were pushed out earlier this month, for laying multiple booby traps and mines across town, endangering the civilian population.
Christians, one of the largest religious minorities at about 10 percent of Syria's pre-war 23 million-strong population, have tried to stay on the sidelines of the conflict.
