AMMAN (Reuters) - Syrian rebel groups who have participated in peace talks said on Sunday that an upsurge in Syrian army shelling and bombing was wrecking the prospects of maintaining a ceasefire brokered by Russia and Turkey.
The rebel groups, mostly backed by Turkey, have attended two rounds of talks in the Kazakh capital Astana. They said they supported a political solution but that war had been "imposed" on them by the Syrian army and its allies.
The groups operating as the Military Delegation of the Revolution said they reserved the right to respond to attacks which have mostly taken place in the south, in Homs and the outskirts of Damascus.
"What is happening ... destroys prospects of a political solution and gives the revolutionary factions the right to an open response to every attack by the regime and its allies," the group said in a statement.
Mohammad Alloush, the head of the Astana talks delegation, said the rebel groups who signed a shaky ceasefire deal late last year that was meant to end bombing of civilians were ready to go back to "all out war".
"If you go back to war, we will (too), and if you go back to peace we will return (to peace)," Alloush told Reuters.
At a first round of the Astana talks in January, Russia, Turkey and Iran, another Assad ally, reaffirmed the ceasefire.
It has been violated repeatedly, with each side blaming the other. Fighting with jihadist groups such as Islamic State which are not included in the truce has raged on.
But in recent days the Syrian army helped by the Russian air force have escalated bombing of rebel-held areas in the southern city of Deraa. The army has also stepped up shelling of rebel-held suburbs of the capital with a rise in civilian casualties.
Reporting by Suleiman Al-Khalidi; Editing by Kevin Liffey/Ruth Pitchford