Rebels say the Syrian army is seeking to recapture an area north-west of Damascus
Syrian rebel groups are backing out of talks about peace negotiations planned by Turkey and Russia, unless the Syrian government and its Iran-backed allies end what it said were violations of a ceasefire.
In a statement, the rebel groups also said that any territorial advances by the army and Iran-backed militias that are fighting alongside it would end the fragile ceasefire brokered by Russia and Turkey – which back opposing sides – that came into effect on Friday.
Rebels allege the rebel-held region of Wadi Barada near Damascus has been subjected to almost-daily bombing raids. In recent weeks, they have also accused the government and its allies of trying to recapture the area, which supplies water to the capital.
The military has denied the allegations which the rebels say jeopardise the entire peace process.
"Any [advance] on the ground goes against the agreement and if things don't return to how they were before, the accord will be considered null and void," the rebel statement said.
On New Year's Eve, the United Nations Security Council voted unanimously to welcome the Russia-Turkey efforts to end the Syrian fighting and to organise peace talks.
The new ceasefire deal applies across Syria but excludes the jihadists of so-called Islamic State (IS) and Jabhat Fateh al-Sham (JFS), and the Kurdish YPG militia.
The peace talks are due to be held in Astana, Kazakhstan.