The main Western-backed Syrian opposition group has begun a three-day meeting in Turkey to discuss a range of issues, including a Russian initiative to hold talks in Moscow on a resolution to Syria's civil war.
The Syrian National Coalition is also expected to elect a new president during the closed-doors proceedings in Istanbul.
Russian diplomats have been meeting the Syrian government and the Coalition to try to arrange talks without preconditions.
The Coalition has not ruled out participating, but has so far insisted that any negotiated settlement be based on the so-called Geneva platform, which calls for the formation of a transitional governing body with full executive powers.
The Syrian government of Bashar Assad has said it is ready to attend.
Moscow, a key supporter of Assad, is backing talks to end a civil war that has killed more than 200,000 people.
Russian diplomats have been shuttling between the sides in recent weeks to sound out their willingness to attend the meeting that the Kremlin has said it hopes to convene after January 20.
Assad's government has said it is ready to attend "preliminary" talks, but says they should pave the way for a conference in Syria itself.
Russia has said that the first stage of talks would include members of both the government-tolerated internal opposition and opposition groups based abroad, including the Coalition. In the next stage, they would be joined by Syrian government representatives.
Elsewhere, UN envoy Staffan de Mistura is attempting to decrease the level of carnage in Syria through a plan that calls for "freezing the conflict" in the northern city of Aleppo as a building block for a wider solution to the war.
So far, there is little to suggest that the UN plan or the Russian initiative has a real chance of success, but analysts say there is a greater chance now for a settlement as a result of recent government losses in the north and south as well as growing resentment towards Assad among his traditional supporters - particularly after the mass killings of soldiers by militants.