Opposition forces in Syria have attacked government positions, calling it retaliation for government airstrikes killing four people. The fighting has undermined a ceasefire deal and threatens UN-led peace talks.
Opposition forces struck government troops in the Latakia province in the north on Monday as well as the outskirts of Hama in central Syria, reported a monitoring group.
The fighting - which also increased around the besieged city of Aleppo - came on the heels of a rebel faction statement announcing the clashes.
"After the increase of violations by regime forces that included targeting displaced people and continuous bombing of residential neighborhoods, we declare the start of the battle in response," said the statement signed by 10 armed rebel groups.
Mohammed Alloush, a high-ranking official of Jaish al-Islam and chief negotiator for the opposition in the UN-backed peace talks taking place in Geneva, called on Sunday for retaliation against the government.
"Don't trust the regime. Hit them at their necks... strike them everywhere," Alloush wrote on his Twitter account.
The opposition accused President Bashar al-Assad's forces of using the Russia and US-brokered ceasefire to encircle opposition-held areas in Aleppo to prepare for an attack.
Deadly government airstrikes
A source in Syria's military confirmed Monday's attacks, likewise accusing the rebel forces of breaking the ceasefire.
"Today they attacked in the northern Latakia countryside in several areas, in violation of the cessation of hostilities agreement, and also in the northwestern Hama countryside," the source said. The source added that the army was continuing to fighting back and had thwarted a car bomb attack in the Ghab plain.
However, the British-based Syrian Observatory for Human Rights reported on Monday that air raids from government forces in the northern Homs province already killed four people. They said that due to numerous injuries, the death toll was expected to rise.
Rocky peace negotiations
The escalating violence in Syria has placed Geneva peace talks convened by UN envoy Staffan de Mistura at risk - with the pressure on to reach a consensus and keep the opposition at the table.
"The opposition is split 50:50 on whether to stay or go," a senior Western diplomat told Reuters news agency.
Initial reports from peace talks in Geneva suggested that the main Syrian opposition HNC sent only three delegates to meet UN envoy Staffan de Mistura on Monday. The HNC also delayed a planned press conference by its chief coordinator Riyad Hijab.
In a meeting on Friday, de Mistura floated the idea of Assad remaining in power symbolically in exchange for the opposition's nomination of three Syrian vice-presidents. The proposal was rejected outright by the opposition.
The Geneva talks aim to end a civil war that has killed more than 250,000 people, created the world's worst refugee crisis, and allowed for the rise of the militant "Islamic State" group.
rs/msh (AP, AFP, dpa, Reuters)