Arab League foreign ministers are expected to back special envoy Kofi Annan's plan to end the crisis in Syria, a day after President Bashar al-Assad's government accepted the proposal.
The foreign ministers are meeting amid heavy security in the Iraqi capital, Baghdad, where Arab leaders will hold a summit on Thursday.
The Arab League suspended Syria's membership last year after Assad's government failed to end its violent crackdown.
Western diplomats and Syrian opposition figures greeted Syria's acceptance of Annan's cease-fire plan with skepticism, as fighting continued between government forces and rebels.
Opposition members accuse Assad of agreeing to the plan to stall for time as his troops make a renewed push to kill off areas of dissent.
U.S. Secretary of State Hillary Clinton called Syria's acceptance an "important initial step," but said what matters now is action.
"Given Assad’s history of over-promising and under-delivering, that commitment must now be matched by immediate actions," she said. "We will judge Assad’s sincerity and seriousness by what he does, not by what he says. If he is ready to bring this dark chapter in Syria’s history to a close, he can prove it by immediately ordering regime forces to stop firing and begin withdrawing from populated areas."
She urged the Syrian government and the opposition to take steps in the coming days to end the bloodshed.
The United Nations said Tuesday the number of people killed in Syria's crackdown has risen to more than 9,000, an increase of about 1,000 over the world body's previous estimate.
In remarks to the U.N. Security Council, Middle East envoy Robert Serry said violence in Syria continues "unabated" and preventing a further escalation of the conflict is "urgent." Damascus blames the revolt on what it says are foreign-backed terrorists.
Several U.S. senators told VOA the Syrian leader must step down, a move not mandated by Annan's peace plan. South Carolina Senator Lindsey Graham said "negotiations with a barbaric regime are going nowhere."
"We should be unified as an international world community, say [to Assad] 'You are going to go. You have got to go'. We should have safe havens for the Syrian people who are being slaughtered," he said. "They should have the ability to defend themselves by having the Arab League and others provide them with weapons and training."
Georgia Senator Johnny Isakson said he does not know of "any solution that makes sense with Assad in place."
Also Tuesday, several-hundred Syrian opposition figures met in Istanbul in an attempt to unify their ranks and win greater recognition from Western and Arab nations in an anti-Assad coalition calling itself the "Friends of Syria." Istanbul is due to host a conference of those nations on Sunday.
Syrian National Council members drafted a declaration calling for a post-Assad Syria to be a "civic and democratic state." But veteran Syrian dissident Haitham al Maleh withdrew from the Istanbul meeting, accusing the SNC of ignoring differing opposition voices.
Some information for this report was provided by AP, AFP and Reuters.