GENEVA - A new round of indirect peace talks beginning Monday will see Syria's government and opposition engage for the first time in concrete discussions on the future of the war-torn country.
The negotiations at the United Nations in Geneva are part of the biggest international effort to date to end Syria's conflict, which has killed more than 270,000 people.
UN special envoy Staffan de Mistura announced that the talks will launch on March 14, the eve of Syria's five-year anniversary as a country at war.
Analysts say much has changed since the last round collapsed in February, but that the huge government-opposition divide will complicate a settlement.
The central obstacles are the fate of President Bashar al-Assad, presidential elections and the type of new government.
The last time the opposition and regime were in Geneva, clashes were raging across the country, especially in the northern province of Aleppo.
But since February 27, a fragile truce brokered by the United States and Russia has largely held despite each side accusing the other of violations.
The reduction in violence has allowed the UN to deliver humanitarian aid to some 240,000 people in 10 out of 18 besieged areas nationwide, a crucial opposition demand.
According to De Mistura, the negotiations will last two weeks and would first discuss an inclusive new government followed by a fresh constitution, then parliamentary and presidential elections in 18 months.
But this agenda "is not realistic," said Joshua Landis, director of the Center for Middle East Studies at the University of Oklahoma.
Despite opposition and Western calls for him to quit, "Assad is stronger than ever and is going nowhere", Landis told AFP.
The Riyadh-based High Negotiations Committee, a broad collection of political and armed opposition factions, has repeatedly insisted that Assad would have no role in a future Syria.
"We will not accept Assad being imposed on Syria as (Russian President Vladimir) Putin's puppet," HNC spokesman Salem al-Meslet said.
For the HNC, Assad must leave power at the creation of "a transitional governance body with full executive powers".
In the opposition's view, this body would manage Syrian affairs while a new constitution is formed and until parliamentary and presidential elections.
But the regime has rejected this structure outright, saying Assad's future is not on the table.
"We will not talk with anyone who wants to discuss the presidency... Bashar al-Assad is a red line," Foreign Minister Walid Muallem told reporters Saturday.
"If they (the opposition) continue with this approach, there's no reason for them to come to Geneva." Muallem also lambasted De Mistura for saying the talks would cover presidential elections, saying the envoy "has no right" to set the agenda.
The government plans to hold both elections as scheduled, with a parliamentary vote next month and a presidential election in 2021 after Assad's seven-year term ends.
It has repeatedly called for a "unity government" with opposition members instead of a transitional period.
The only point of agreement between both sides is the categorical rejection of a federal system.
Syria's Kurds have carved out autonomous zones in the north and northeast, hoping that a federal system would allow them independent rule there.
The leading Kurdish party in Syria, the Democratic Union Party (PYD), was not invited to either round of talks.
On Saturday, De Mistura told Swiss newspaper Le Temps that although the Kurds were not invited, they should be allowed to voice their views on Syria's political future.
Russia and the United States back opposing sides in the war but have increased co-operation in efforts to find a solution.
About half of Syria is controlled by either the Islamic State group or Al-Qaeda's local affiliate, hindering the implementation of any agreement.
"Asking the Syrian actors to agree has proven unsuccessful... because their ideological and territorial disagreements are so profound," Landis said.
"But all actors are so entirely dependent on their sponsors that they must comply with the wishes of their armourers," he said.
Andrew Tabler, Syria expert at the Washington Institute for Near East Policy, says the US-Russian rapprochement will not be enough.
"Have the United States and Russia agreed on the need to settle down the Syria conflict? Yes. On a workable formula for doing so? No."