Syrian air raids on rebel positions in the northern Aleppo and southern Daraa provinces killed 30 people on Thursday, including civilians, a monitoring group said.
With the world's attention trained on Syria's chemical weapons, set to be destroyed by international experts under a UN resolution, the latest deaths highlighted the lethality of the regime's conventional arsenal.
Fighting has raged in Syria's onetime commercial hub of Aleppo, where President Bashar al-Assad's regime and rebels have battled street by street for neighbourhoods and supply routes.
The raids by planes and helicopters on Thursday killed 16 people, including a woman and two children in the village of Sfire to the east of the city, according to the Syrian Observatory for Human Rights.
The village is controlled by Islamist groups, including the Al-Qaeda-affiliated Islamic State of Iraq and the Levant (ISIL).
"The regime has bombarded Sfire for two days in order to relieve pressure on the supply route to Aleppo," which the army reopened earlier this week, said Rami Abdel Rahman, head of the Britain-based group, which relies on a network of activists across the war-torn country.
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The route is used not only to ferry weapons and reinforcements to troops at the front, but also to deliver food and medical supplies to civilians in regime-controlled areas.
Another six people, including a woman and a child, were killed in air raids on Menbej, another village east of Aleppo controlled by ISIL and other Islamist groups.
In the southern province of Daraa, where the uprising began in March 2011, eight people, including two children, were killed in air raids on Nawa village, split between the army and rebels.
The General Commission of the Syrian Revolution said there were many people wounded and in serious condition, indicating the toll would rise.
At another front close to Damascus, fierce fighting broke out pitting government troops backed by the Lebanese Hezbollah and pro-regime militiamen against rebels in Bueida and Dyebiye near Sayyeda Zeinab, site of a revered Shiite shrine.
Fighting has been under way for months in the area, where Shiite Hezbollah fighters have long been deployed to assist regime forces and protect the shrine.
State news agency Sana said the army was able to seize control of Dyebiye and Husseiniyah, another nearby district.
The Observatory said troops had seized the nearby villages of Sheikh Amro and Bassatine.