The United States and its European partners are threatening new sanctions on Syrian President Bashar al-Assad's government, but the fractured and frustrated Syrian opposition is seeking military action instead.
About 100 delegations are meeting in Paris on Friday at the "Friends of Syria" conference aimed at bolstering the Syrian resistance and pressing Syria's allies to discuss transition strategies after 16 months of violence.
Francois Hollande, the French president, in the opening statement on Friday, said: "Our meeting must set itself a goal to encourage the UN Security Council to take a responsibility to draw a plan to come out of the crisis."
Hassan Hashimi, general secretary of the opposition Syrian National Council, said the international community is still moving too slowly.
Going into Friday's meeting, he said he hopes to see a "tough stand'' by diplomats, and a no-fly zone to prevent military forces "flying over defected soldiers and civilians and bombarding them''.
The meeting comes amid reports that Manaf Tlas, a Syrian general and personal friend of Assad, was traveling to Paris after he defecting from the Syrian army.
The meeting follows a gathering in Tunis, and another in Istanbul, both of which called in vain for tougher action against Assad's government.
China and Russia did not attend either of those meetings in which the United States, France, Britain, Germany as well as Saudi Arabia and Qatar, gathered with a group of more than 60 nations, including most European Union and Arab League states.
UN Security Council members, the US and France will lead calls at the Paris talks for tough new UN sanctions to be imposed on Assad and his inner circle.
One US official said it was time "to put this all together under a Security Council resolution that increases the pressure on Assad, including having real consequences".
"We believe most of the countries represented in Paris think that has to include Chapter 7 economic sanctions on Assad," said the official aboard Clinton's plane who requested anonymity, referring to a clause within the UN charter.
"Many of the countries in Paris already have those sanctions but globalising them will be very important. That is the argument that we will continue to make to Russia and China."
Chapter 7 of the UN Charter allows for sanctions ranging from economic measures to an arms embargo, and, if necessary, military force.
The measure was last used against Libya in 2011. It could be highly controversial at the UN Security Council, given Russia and China's veto powers.
Laurent Fabius, the French foreign minister, told Le Parisien newspaper on Friday that "several things" would be decided at the talks, including a call for Chapter 7 backing.
"Broadening the sanctions on the Syrian regime, supporting the opposition by supplying means of communication, supporting humanitarian networks and calling for the text adopted last week to be sent to the UN Security Council to be made obligatory with the framework of Chapter 7 of the UN Charter," he said.
China backed Russia at talks in Geneva last weekend, insisting that Syrians must decide how the transition should occur, rather than allowing others to dictate their fate, and did not rule out Assad remaining in power in some form.
The West insists that Assad should not be part of any new unity government and the Syrian opposition rejected the Geneva talks as making concessions to Damascus under pressure from Russia.