Syrian regime forces on Saturday pounded rebel positions in central Homs province, with 18 people killed in violence across the country, including 13 civilians, a monitoring group reported.
The latest deaths come just hours after more than 90 people were reportedly massacred by regime forces in the town of Houla, also in Homs province.
"A civilian was killed during the shelling of Qusayr," a rebel bastion in Homs and scene of frequent clashes between regime troops and rebel fighters, the Syrian Observatory for Human Rights said.
"In the city of Homs, blasts were heard this morning as well as heavy machinegun fire in the Jobar district," the Britain-based monitoring group said, adding that three other civilians were killed in the restive province.
In Ariha in northwest Idlib province, two civilians were killed by shells, the rights watchdog said.
Mohammad Riad Haj Ahmad, a young activist, was killed and another 10 people were injured when regime forces opened fire on demonstrators in Saraqeb, also in Idlib, according to the same source.
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Protesters in Saraqeb had cut off the road linking Aleppo and Damascus, to condemn the massacre committed by regime forces in Houla, the rights watchdog said.
In the capital, one woman and two men were killed in the Qadam neighbourhood in a shooting, while another civilian was killed by sniper fire in Damascus province.
In southern Daraa, three civilians, including two women, were killed when regime forces shelled the village of Khirbit Ghazala.
Also in Daraa, regime forces raided Qarfa village and detained scores of residents, while five regular soldiers were ambushed and killed in the same region, the Observatory added.
In Aleppo, Syria's second city, thousands of people took to the streets on Saturday, during a funeral in the Seif al-Dawla district, to condemn the Houla massacre and call for the fall of President Bashar al-Assad.
Other demonstrations took place, including a several hundred-strong protest in Hama denouncing both the Syrian regime and the international community, according to videos posted by activists on Youtube.
Protests also took place in Daraa and Damascus, the Observatory said.
The watchdog said more than 110 people have been killed by regime forces since Friday, when large demonstrations were held across the country, including Aleppo, a traditional bastion of Assad's regime.