Syrian regime warplanes resumed their bombardment of a opposition-held valley near Damascus on Sunday after nearly 24 hours with no air raids, an opposition official and monitors said, during the third day of a fragile ceasefire.

The truce deal, brokered by Russia and Turkey which back opposing sides in the conflict and welcomed unanimously by the United Nations Security Council, has been repeatedly violated since it began.

Opposition forces on Saturday warned they would abandon the truce if the regime side continued to violate it, asking the Russians, who support Bashar al-Assad, to rein in army and militia attacks in the valley by 8:00 p.m.

Bombardments ceased before that time - although some clashes continued - but began again late on Sunday.

It was not immediately clear if the opposition forces would abandon the truce as a result. Like previous Syria ceasefire deals it has been shaky from the start with repeated outbreaks of violence in some areas, but has largely held elsewhere.

The raids hit areas of Wadi Barada, where regime forces and their allies launched an operation more than a week ago, a spokesman for the Jaish al-Nasr opposition group and the British-based Syrian Observatory for Human Rights said.

There was a "fierce attack and attempt by Assad and Shi'ite militias to raid Wadi Barada" from nearby hills, the opposition spokesman, Mohammed Rasheed, said.
State media and the Observatory said hundreds of people had left Wadi Barada in the past day for government-controlled areas nearby.

Earlier on Sunday regime warplanes carried out several air strikes in the southern Aleppo countryside, the Observatory and rebel officials said.

Regime forces also advanced overnight against opposition forces in the Eastern Ghouta area near Damascus, seizing 10 farms, the Observatory said.

A second opposition official suggested that low-level clashes on the ground would not necessarily derail the truce, but that air strikes were a "clear violation".

PHOTO CAPTION

Children play near rubble of damaged buildings in al-Rai town, northern Aleppo countryside, Syria December 25, 2016.

Reuters