Hassan Abdel Azim, head of the National Coordination Committee for Democratic Change, an internal opposition group, said Vienna had set out a "practical plan".

"Everything that happens in Vienna, we agree with and is in line with the vision of the NCCDC for a political solution," he said.

But he cautioned that the process remained "open to amendments".

Confidence-building measures, including a ceasefire, prisoner releases, and aid deliveries were all "steps that pave the way for a transitional period, forming a government, and holding elections", Abdel Azim said.

- Ceasefire 'far from reality' -

Syria's conflict began with anti-government protests but later fractured into a multi-front war between the regime, rebels, Kurds and jihadists, with shifting military alliances.

UN peace envoy to Syria Staffan de Mistura was tasked at Vienna with bringing about a ceasefire between warring groups.

But Fares Buyush, head of the Fursan al-Haq rebel brigade fighting in north and northwestern Syria, said the decisions reached in Vienna were "far from reality" and that a ceasefire would be "very difficult" to implement.

And Asaad Hanna, a spokesman for the Division 101 rebel group, said Vienna's goals -- including a ceasefire -- were divorced from the reality of forces fighting both IS and Assad's troops.

"Just because the international community holds a press conference, it doesn't mean they're going to stop Daesh," Hanna said.

"The uprising is happening on the ground. How can the meetings exclude the decision-makers on the ground, who would be the ones implementing the ceasefire?"

Bitar agreed: "On the ground, this roadmap won't change very much in the short term."

"As long as the details have not been discussed and the timeline remains vague, each camp will first seek to consolidate its positions," he said.

On Sunday Damascus remained vague in its response to Vienna.

"Syria has always believed that the political process was necessary to reach a solution," Information Minister Omran Zohbi said.

"The political process should respect national sovereignty and the choice of the people in designating their leaders and president."

Source: AFP