The army killed at least 26 civilians on Saturday, including 17 in the flashpoint southern city of Daraa, while three soldiers died in clashes in northern Syria, a monitoring group said.
Nine women and three children were among the 17 killed in a pre-dawn bombardment of a residential neighbourhood of Daraa, the Syrian Observatory for Human Rights said.
Dozens more were wounded, some of them seriously, in the city which was the birthplace of the uprising against President Bashar al-Assad's rule that erupted in March 2011, the the British-based watchdog said.
Also in Daraa province, security forces opened fire in a raid on the village of Abtaa, wounding a number of people and making nine arrests, according to the Observatory.
In Homs city of central Syria, government forces pounded the rebel-held Khaldiyeh, Jouret al-Shiyah, Al-Karabis and Qusayr districts with artillery and mortar fire in an bid to regain control.
Six people were killed in the bombardment, the watchdog said.
Elsewhere in the province, "the town of Talbisseh was shelled by regime forces, which had suffered losses several days before when rebels took control of their checkpoints in the town," it said.
In the northern province of Aleppo, three regime troops were killed in clashes in the town of Andan, which was shelled.
Also in Aleppo, regime forces bombarded the towns of Hayyan and Beyanoun, killing one civilian and wounding four others.
In Latakia province on the Mediterranean, two civilians were killed in regime shelling of the city of Al-Heffa and neighbouring villages, on the fourth day of an operation to retake control of the areas, the Observatory reported.
"Al-Heffa is a Sunni town, in a mixed Sunni and Alawite region," Observatory head Rami Abdel Rahman told AFP by telephone.
A total of 46 soldiers, 16 civilians and 18 rebel fighters have been killed in the assault on Al-Heffa, according to the watchdog. Syrian state television on Saturday blamed the violence on "armed terrorist groups."
More than 13,500 people have been killed across Syria since the uprising broke out, according to the Observatory's figures.