About 10 Syrian opposition groups announced Monday they were suspending talks about participating in planned peace negotiations this month in the Kazakh capital Astana, due to "violations" by the regime of a four-day-old truce.
In a statement, the groups also said that any territorial advances by the regime forces and Iran-backed militias that are fighting alongside it would end the fragile ceasefire brokered by Russia and Turkey that came into effect on Friday.
"As these violations are continuing, the rebel factions announce ... the freezing of all discussion linked to the Astana negotiations," they said in a joint statement, referring to talks planned for late January organised by Russia, which supports the Syrian regime, and Turkey which back the rebels.
They said they "respected the ceasefire across the whole of Syria ... but the regime and its allies have not stopped shooting and have launched major and frequent violations, notably in the opposition-held Wadi Barada and Eastern Ghouta," both in the province of Damascus.
"Despite repeated questions put to the regime's backer," Russia, "these violations continue, threatening the lives of hundreds of thousands of people," said the statement.
— Ruslan Trad (@ruslantrad) January 2, 2017
For the last two weeks, even before the start of a global truce brokered by Ankara and Moscow with a view to enabling the Astana talks to take place, the Syrian regime's air force has launched almost daily bombing raids on Wadi Barada, some 15 kilometres (10 miles) from Damascus.
The regime of Bashar al-Assad is trying to seize control of the region which supplies the main drinking water for the four million inhabitants of the capital and surrounding areas.
On Monday, the regime forces and the Lebanese Shia militant group Hezbollah advanced to the outskirts of Ain al-Fijeh, the primary water source in the area, said the war monitor, Syrian Observatory for Human Rights.
"Any (advance) on the ground goes against the (ceasefire) agreement and if things don't return to how they were before, the accord will be considered null and void," added the opposition statement.
The ceasefire, which has been in force since midnight Thursday, is the latest truce in the nearly six-year war which has killed more than 400,000 people and displaced millions.