Secretary of State Hillary Clinton Friday held "constructive" talks with her Russian counterpart Sergei Lavrov over a draft UN Security Council resolution condemning Syria's crackdown, officials said.

The pair agreed that diplomatic teams from both countries would "continue to consult" on the draft in New York, said State Department spokesman Mark Toner, amid a US push for passage of the resolution.

The latest draft does not explicitly call on Syrian President Bashar al-Assad to step down or mention an arms embargo or sanctions, though it "fully supports" an Arab League plan to facilitate a democratic transition, a senior State Department official said earlier Friday.

"We're cautiously optimistic," the official, who spoke on condition of anonymity, said about winning Russia's support.

The latest attempt at consensus emerged amid an impasse in the UN Security Council, with Russia leading the opposition to a tougher draft resolution authored by Western powers and the Arab League.

The January 22 Arab League plan calls for Assad to transfer power to a deputy and a government of national unity within two months but does not call on him to step down, according to a copy obtained by AFP.

Clinton was Friday on her way to an international security conference in Munich.