Apprehension over US-Russia Syria deal

US Secretary of State John Kerry hailed it as a potential "turning point." UN Syria envoy Staffan de Mistura called it a "window of opportunity." But, for many outside observers - including members of a key Syrian rebel group - the ceasefire deal touted on Friday was a cause for immediate skepticism rather than celebration.

After 13 tense hours of negotiations, Kerry and Russian Foreign Minister Sergey Lavrov stood before reporters in Geneva to outline the details of the arrangement, which will take effect on Monday to coincide with the Islamic holiday Eid al-Adha. If both sides, including the Russian-backed regime of Bashar al-Assad and US-supported rebels fighting to topple him, manage a complete cessation of hostilities for a full week, Washington and Moscow will work together in targeting the "Islamic State" (IS) and a Qaeda-linked group formerly known as Nusra Front.

Even Kerry himself sought to temper enthusiasm by calling the plan "an opportunity and not more than that until it becomes a reality." That reservation was shared by others, including members of the Northern Division and the Harakat Nour al-Din al Zinki Brigades, both factions of the internationally backed Free Syrian Army.

Major obstacles

There's reason to be pessimistic. All previous attempts to bring about a peaceful resolution to the over-five-year conflict have failed. The last ceasefire was agreed upon in February, but broke down after only a few weeks following repeated violations by both sides.

For Washington, central to the deal is Russia's putting pressure on regime forces to withdraw from besieged areas around rebel-held Aleppo in order to allow the delivery of humanitarian aid. For Moscow, a key point is having the US convince rebel forces to disassociate themselves from Nusra Front, which renamed itself Jabhat Fateh al Sham in July.

The challenges posed by this latest ceasefire plan have left few speaking of the elusive resolution to the war that the international community has long hoped for.

"We're always going to be cautiously optimistic, but we've seen this time and time again," Yasmine Nahlawi, of Rethink Rebuild Society, a UK-based community organization that focuses on Syria's conflict, told DW. "I don't see any reason for this one to be any different."

'Marginally more optimistic'

Nahlawi said that in order for the ceasefire to work there would need to be consequences for those who violate it. "The one thing that's missing from everything is enforcement," she said, suggesting the US-led alliance could implement "no bombing zones" in civilian areas and target regime forces when they fail to abide by them. But she also acknowledged that the US wanted to avoid a direct confrontation with Russia.

One of the major difficulties in implementing the deal will be convincing rebel forces to disavow Jabhat Fateh al Sham, one of the most powerful groups fighting Assad's forces. Not only has the group eliminated rebels opposed to it, but it has also proved to be one of the most assured fighting forces in besieged Aleppo.

Reinoud Leenders, an expert on Syria at King's College London, told DW that he is "marginally more optimistic" about this deal than the previous one, but also said the ceasefire could prove unworkable if the United States and Russia were to go after Jabhat Fateh al Sham as many rebels depend on the group. "If [the US and Russia] are going to step up during the ceasefire and carry out strikes against Nusra, then the whole thing will break down," he said, using the group's former name.

Leenders also remains doubtful about a political solution. "I don't think any peace agreement will follow from ceasefires like this," he said. "The regime is not in the mood to do that, and the rebels are in an existential situation. If they lose Aleppo, it's basically end of story for them."