Shelling has resumed in two government-held villages in northwest Syria and the rebel-controlled town of Zabadani near Damascus, state media and a monitoring group have said, as a ceasefire covering the areas collapsed.
The violence on Saturday came following reports that talks aimed at extending a truce that began on Wednesday have collapsed.
Abu Jaber al-Sheikh, spokesman of Ahrar al-Sham rebel group, confirmed to Al Jazeera that negotiations are over.
He blamed the Syrian government and Iran for the collapse of the negotiations, claiming that pro-government negotiators have demanded that rebels as well as civilians leave Zabadani.
Syrian state television said a child and her father had been killed and 12 others wounded in "terrorist shelling" on the regime-held villages of Fuaa and Kafraya in Idlib province.
The Syrian Observatory for Human Rights, a British-based monitor, said rebels had fired about 20 missiles at the two villages and also reported shelling on the rebel-held town of Zabadani.
In Fuaa, a resident who spoke on condition of anonymity confirmed the bombardment.
"Today we've been hearing the sound of explosions since dawn," the resident said. "The truce failed and the attacks have resumed."
The truce agreement between rebel groups and pro-regime factions, including Lebanon's Shia Hezbollah group, came into effect in the early hours of Wednesday morning.
Before its expiry on Saturday morning, intensive negotiations had been under way for an extension of the ceasefire and a full deal.
Breaches in the ceasefire
The talks centred on the withdrawal of rebels from Zabadani and the evacuation of civilians from Fuaa and Kefraya, which are the last two government-held villages in Idlib province.
But the negotiations reportedly stumbled over an opposition insistence that thousands of prisoners be released from government jails, according to Observatory chief Rami Abdel Rahman.
"It's not clear if the breaches are attempts by the parties to improve the conditions of the deal or come from those who want to thwart the negotiations," he said.
The temporary ceasefire was a result of mediation by Turkey, which backs rebels fighting against President Bashar al-Assad, and Iran, whose support has been vital to his survival, reports said.
It was among the strongest signs yet of a new regional approach toward a conflict that has killed a quarter of a million people, made 10 million homeless, left swathes of Syria in the hands of the Islamic State in Iraq and the Levant (ISIL) and divided the countries of the Middle East on sectarian grounds.
Source: Al Jazeera and agencies