Army rocket fire on a central Syrian village on Wednesday killed at least 12 people including women and children, a watchdog said, as warplanes attacked rebel enclaves near central Qusayr.
Aircraft also struck Karam Huweimed and Tariq al-Bab in the northern city of Aleppo, as well as a rebel-held town nearby, said the Syrian Observatory for Human Rights.
"The number of people killed in rocket fire by the army on eastern Bweida has risen to 12, among them a boy and a girl, two women, and eight men," said the Observatory, referring to the village in the central province of Homs.
Nearby, clashes killed three rebel fighters close to the town of Abel, said the Britain-based group, adding that "regime troops used warplanes and rocket fire".
Fighting also raged in other flashpoint areas of Homs province.
"The regime is relying on fighters loyal to (Lebanese Shiite movement) Hezbollah and the (pro-regime paramilitary) National Defence Forces to root out rebel fighters in the Homs countryside," said the Observatory's Rami Abdel Rahman.
"The army is trying to isolate rebels in Qusayr and to defeat the insurgency in the countryside," he told AFP.
The area is key because it lies on the road linking Damascus to the coast. It has seen frequent violence ever since the outbreak of the insurgency, and activists say shelling there has intensified in recent days.
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Pro-regime newspaper Al-Watan said the army kept up its efforts to break rebel sieges on several airports in Aleppo province.
"In Aleppo, the army made progress in its plan to open up the main supply route leading to the barracks in... the Nayrab and Aleppo international airports," said the daily.
Adjacent to Nayrab, Aleppo international airport has been closed since January.
Rebels meanwhile kept up their siege on Kwayris military airport, also in Aleppo province, said the Observatory.
"Warplanes staged an air strike on Karam Huweimed" in Aleppo's provincial capital, while fierce clashes pitting insurgents against troops raged in the area, the Observatory said.
The air force also fired on Tariq al-Bab in eastern Aleppo city, a rebel stronghold frequently targeted by the army, while at least one person was killed in an air strike on Azaz in Aleppo province.
Wednesday's violence comes a day after at least 99 people -- including 41 civilians -- were killed across Syria, said the Observatory, which relies on a network of activists, doctors and lawyers for its information.
More than 70,000 people have been killed in Syria's two-year conflict, the UN says.