Regime forces on Sunday pressed a fierce offensive in Homs after overrunning a key neighbourhood of the central city, according to a watchdog, which also listed 23 children killed in violence across Syria.
The latest bloodletting comes after international peace envoy Lakhdar Brahimi warned in Moscow that Syria was facing a choice between "hell or the political process" after talks with Russian Foreign Minister Sergei Lavrov.
The Syrian Observatory for Human Rights said the army, after Saturday seizing the Deir Baalbeh district in fighting which left dozens dead, fired off barrages of rockets into surrounding rebel-held neighbourhoods Sunday as it sought to capitalise on its victory.
Troops also bombarded the nearby opposition stronghold of Rastan.
The Britain-based Observatory, which gathers its information from a network of activists and medics in civilian and military hospitals, said the final death toll from Saturday's clashes had not been finalised due to communications difficulties in the area.
A video released by the Syrian Revolution General Commission, a grassroots network of anti-regime activists, showed the bodies of nine male victims from Deir Baalbeh lying on the ground, their faces bloody and mutilated.
The authenticity of the video could not immediately be verified.
Near the capital on Sunday, loyalist troops carried out air raids on towns along the eastern outlying belt and on Daraya in the southwest, while fighting between rebels and the army erupted in the northeastern and southwestern suburbs.
The Observatory said 13 children were among the victims of bombardments in and around Damascus on Saturday, while 10 children were killed in air strikes across Aleppo province, including on rebel-held Aazaz near the Turkish border.
Analysts say the surge in air strikes by Syrian forces are a desperate attempt by President Bashar al-Assad's regime to reverse rampant gains by rebel fighters, especially in the north of the country.
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Rebels meanwhile made further advances on Sunday in the battle for the Hamidiyeh military post in the northwest province of Idlib which they stormed the previous day, the watchdog said.
During Sunday's clashes, three insurgents were wounded by machinegun fire, while warplanes raided a nearby village, the watchdog said.
A takeover of the Hamidiyeh post would pave the way for a rebel offensive against the the nearby Wadi Deif base, one of the government's last outposts in the north.
Opposition fighters, mostly from the jihadist Al-Nusra Front, have been closing in on the base since overrunning the nearby town of Maaret al-Numan in early October.
In the south, a rebel was killed on Sunday in battles for control of several small border crossings along the regime-held frontier with Jordan, the Observatory said.
Syria and Jordan share a 370-kilometre-long (230-mile) border which hundreds of people cross on foot every day to escape the bloody civil war that the Observatory says has killed at least 45,000 people.
Brahimi on Saturday held talks with Lavrov on his end-of-year bid to accelerate moves to halt the Syria conflict.
He painted a stark picture of Syrian neighbours Jordan and Lebanon being overrun by a million refugees should heavy fighting for the seat of power break out in Syria's five-million-strong capital.
If this fighting "develops into something uglier... (refugees) can go to only two places -- Lebanon and Jordan.
"So if the alternative is hell or the political process, we have all of us got to work ceaselessly for a political process," Brahimi said.