Arab countries are pushing ahead with a symbolic United Nations General Assembly resolution that tells Syrian president Bashar Assad to resign and turn over power to a transitional government.
It also demands that the Syrian army stop its shelling and helicopter attacks and withdraw to its barracks. A vote on the resolution will be held on Friday.
The draft resolution circulated on Wednesday takes a swipe at Russia and China by "deploring the Security Council failure" to act. Moscow and Beijing have used their veto in the smaller, more powerful UN council three times to kill resolutions that could have opened the door to sanctions on Syria.
While the 193-member general assembly has no legal mechanism for enforcing a resolution, an overwhelming vote can carry moral and symbolic power. Voting is by simple majority and there is no veto.
The UN reported a significant escalation in Syria's civil war on Wednesday, with the military using warplanes to fire on opposition fighters in the 12-day battle for Aleppo.
The general assembly draft resolution, written by Saudi Arabia and lobbied for by Egypt and Bahrain, is an attempt to get around the stalemate in the security council.
"What's important here is that a meeting of the general assembly on this topic would be an expression of the frustration felt in the international community at large about what's happening in Syria and the inability of the international community, so far, to be able to help bring an end to the violence that everybody wishes to see," said Martin Nesirky, spokesman for UN secretary general Ban Ki-moon.
France, which has taken over the security council presidency for August, has called for a foreign minister-level meeting of the council to address the Syria crisis. It was not clear what that could accomplish.
UN officials said the Arab countries might be ready to weaken some provisions of the draft resolution to guarantee a larger majority vote. The last general assembly resolution on Syria had 137 votes in favour. A security council diplomat said the Arab sponsors of the resolution had decided to make some "tweaks" in the text after receiving reaction from other delegations yesterday and were working to build the majority.
The resolution condemns the increasing Syrian military reliance on heavy weapons, including tanks and helicopters, and the "failure to withdraw its troops and heavy weapons to their barracks" in line with a set of proposals by UN-Arab League envoy Kofi Annan, the former UN secretary general who has been trying to mediate the crisis. The resolution backs Mr Annan's demand that "the first step in the cessation of violence has to be made by the Syrian authorities".