Russia has said it will veto a UN resolution to refer the Syrian conflict to the international criminal court (ICC) if it comes to a vote in the security council, after nearly 60 countries announced their support for the measure.

Moscow's position, announced on Tuesday by Gennady Gatilov, the deputy foreign minster, is consistent with previous moves to protect Bashar al-Assad, the Syrian president, from international censure in more than three years of a war that has cost 160,000 lives and displaced millions of people.

"The draft that has been submitted to the UN security council is unacceptable to us, and we will not support it," Gatilov was quoted as saying by Interfax news agency. "If it is put to a vote, we will veto it."

France first circulated the proposal last month after briefing the security council on photographic evidence, provided by a defector, of mass killings of detainees by the Syrian government. It calls for the ICC to be given a mandate over crimes against humanity and war crimes committed in Syria.

The security council is expected to vote on Thursday. China is expected to follow Russia and use its veto. Britain, the US and the other governments that back the referral say the resolution still has symbolic and moral value.

The 58 countries, led by Switzerland, appealed to all 193 UN member states to co-sponsor the resolution, under which the ICC would be authorised to investigate allegations of heinous crimes by the Syrian government, pro-government militias, and armed opposition groups. They condemned "widespread violations of human rights and international humanitarian law committed in a pervasive climate of impunity by the Syrian authorities and pro-government militias as well as by non-state armed groups." The draft resolution deliberately does not target one side.

Syria is not a party to the statute that established the ICC, so the only way it can be referred to the tribunal at The Hague is by the UN security council. The council has previously referred conflicts in Darfur and Libya to the ICC.

Richard Dicker, director of international justice at Human Rights Watch, said the mobilisation of countries far beyond the five permanent and 10 rotating members of the security council did not happen in the cases of Darfur and Libya.

"This engagement will raise the political price tag for Russia or China should they decide to obstruct justice for Syria through casting a veto," Dicker said. "Referral to the ICC is the best means to bring justice to those who have suffered and signal that the space for impunity for those crimes is shrinking."

The draft resolution takes note of reports by an independent commission appointed by the UN Human Rights Council to investigate violations in Syria. In its latest report last September, the commission said there had been at least eight massacres perpetrated by Assad's government and its supporters and one by rebels in the previous year and a half. A confidential list of suspected criminals is being produced by the commission and kept by the UN high commissioner for human rights, Navi Pillay.