The Syrian opposition on Saturday reacted with caution to a US-Russian ceasefire agreement aimed at curbing violence in Syria and relaunching a UN-sponsored political process.
The High Negotiations Committee (HNC), an opposition coalition, welcomed the agreement but called on Russia, a major ally of Syrian President Bashar al-Assad, to pressure his regime to comply with the deal.
"We hope this will be the beginning of the end of the civilians' ordeal," an HNC member, Bassma Kodmani, said.
"We welcome the deal if it is going to be enforced. What if Russia doesn't pressure the regime, because that is the only way to get the regime to comply? We are waiting with a lot of anxiety," she added in a statement.
The US and Russia's top diplomats announced the agreement late Friday after more than 12 hours of talks in Geneva.
The accord includes a truce that is set to start across Syria at sunset on Monday.
It also foresees joint military strikes against militant groups in Syria, including Islamic State.
US Secretary of State John Kerry, emerging from talks with Russian Foreign Minister Sergei Lavrov late Friday, said the deal could provide a "turning point" in Syria's conflict if the parties implement it "in good faith."
The US is supporting opposition forces fighting to oust al-Assad.
The plan would ensure that the Russian-backed Syrian government does not fly combat missions over rebel-held areas, which would allow humanitarian aid to reach people in need.
Lavrov said Russia had spoken to the Syrian government, which had given its support for the agreement.
There is no official Syrian comment yet on the plan.
However, Samir al-Nashar, a member of the opposition Syrian National Coalition, cast doubt on the agreement.
"We will have to wait and see if the regime and its allies, including the Russians, will adhere to this ceasefire," he told dpa by phone.
"This agreement will be tested because we do not trust the regime and its allies in view of previous experiences on ceasefires."
In February, the US and Russia brokered a ceasefire that held for some time in most parts of Syria.
Later, the truce collapsed under pressure from localized fighting and a failed UN-backed political process to end the violence.
German Foreign Minister Frank-Walter Steinmeier welcomed the new agreement between Washington and Moscow, describing their negotiations as a difficult process "due to differing interests."
He called upon "all parties to the conflict, in Syria and in the region, to adhere to the agreements made between Washington and Moscow and to cease fighting by Monday at the latest."
"If the ceasefire is successfully implemented nationwide, then this is a real, new chance for the humanitarian access so urgently required for hundreds of thousands of people in need," Steinmeier said.
Syria's conflict started with peaceful anti-government protests in March 2011.
It soon spiralled into a full-blown war that has claimed more than 250,000 lives, according to activist estimates.
Some 4.8 million of Syria's pre-war population of 22.4 million have fled abroad, with another 8.7 million predicted to be displaced inside the country in 2016, according to the UN refugee agency.