France circulated a draft resolution to UN Security Council members that seeks to refer the three-year-old civil war in Syria to the International Criminal Court for possible prosecution of war crimes and crimes against humanity.
The 15-member council is due to meet today to discuss the draft submitted on Monday and it could be voted on within days, diplomats said.
But Russia - a veto-wielding council member and ally of Syrian President Bashar al-Assad - has made clear it is against such a move. Russia, supported by China, has already blocked three resolutions that would have condemned Assad's government, threatened sanctions and called for war crimes accountability.
Russian UN Ambassador Vitaly Churkin has reinforced Moscow's stance against referring Syria to The Hague-based court, saying: "Our position has not changed."
More than 150,000 people have been killed in the Syrian conflict. Some 2.5 million have fled abroad and nine million people inside the country need help, a third of them with no access to essential goods and services.
Investigators from the UN said in March that they had expanded their list of suspected war criminals from both sides in the civil war and that the evidence was solid enough to prepare any court indictment.
UN human rights chief Navi Pillay told the Security Council last month that human rights violations by Syrian government forces "far outweigh" those by armed opposition groups.