The Syrian army said on Monday it would suspend combat operations in southern Syria until Thursday ahead of a new round of peace talks in the Kazakh capital Astana, but rebels said the army had already violated the ceasefire by striking areas under their control, APA reports quoting Reuters.
The army general command said in a statement carried on state television the ceasefire began at midday (0900 GMT) on Sunday and was to support "reconciliation efforts", in the second such unilateral ceasefire in the last two weeks.
Hours after the announcement, rebels and witnesses said Syrian jets resumed dropping barrel bombs - drums or cylinders packed with explosives and shrapnel that cause indiscriminate destruction on the ground - on rebel-held areas in the southern border city of Deraa, the town of Naima to its east and countryside near the provincial city.
There was no immediate comment from the army on the rebel allegations.
Russian-sponsored talks are planned in Astana on Tuesday. The last round of Astana talks in May led to the signing of an agreement between Iran, Russia and Turkey to create four de-escalation zones in Syria, one of which is in the south.
But the Syrian army has in recent months escalated its strikes in Deraa in a campaign to reach the border with Jordan and wrest full control of the city.
Hostilities have expanded to the border province of Quneitra along the Israeli-occupied Golan Heights where rebels are waging an offensive against the army and Iranian-backed militias in the strategic border area.
A rebel official said the latest ceasefire was a ploy to drag the opposition to Astana. The rebel side has already expressed deep misgivings about the de-escalation zones, which they say benefit the Syrian army by freeing forces to allow them to make territorial gains elsewhere.
The Syrian opposition and rebel groups accuse Russia of abetting the Syrian army in its major offensive to wrest full control of Deraa.
Some rebel factions are expected to be absent from the Astana talks because of what many see as Russia's unwillingness to end air strikes and its failure to get the Syrian army and Iranian backed militias to abide by a ceasefire, a rebel source said.
"This ceasefire is an attempt by the Russians and the regime to bring back the opposition to Astana and give them assurances on the ground they will stop the shelling on condition they attend," said Sohaib Alraheel, spokesman of Liwa al Furqan Brigades, a faction of the rebel Free Syrian Army (FSA) operating in southwest Syria.