As fighting raged for Syria's commercial capital Aleppo on Monday, at least 12 people were killed in violence elsewhere, seven of them civilians, the Syrian Observatory for Human Rights said.
A teenage boy was killed by sniper fire in Madamiyeh al-Sham, outside Damascus, where troops set up checkpoints during the night, the Britain-based watchdog said.
Unidentified gunmen assassinated civilian pilot Firas Ibrahim al-Safi on the road to Damascus airport, it added.
The pilot's father, General Ibrahim al-Safi "held senior positions in the military leadership under president Hafez al-Assad," late father of incumbent Bashar al-Assad.
In Daraa province, south of the capital, three rebel fighters were killed in clashes with troops, while sniper fire killed a civilian, the Observatory said.
In the eastern province of Deir Ezzor, pre-dawn gunfire killed a civilian in the town of Albu Kamal on the Iraqi border.
One soldier was killed in Damascus province and one in Idlib in the northwest.
In the central province of Homs, regime forces kept up their shelling of the rebel-held town of Rastan.
"Two civilians were killed today when their house was shelled," the Observatory said, adding that several neighbourhoods of Homs city were also shelled.
"Every quarter of an hour, a blast is heard in Homs."
The new head of the UN observer mission in Syria said he saw heavy shelling of Homs during a Sunday field visit and major damage in Rastan.
"During my visit to Homs, I was personally able to witness heavy shelling from artillery and mortars ongoing in the neighbourhoods of the city," Lieutenant General Babacar Gaye told reporters.
"Rastan was heavily damaged by an intensive shelling campaign and fierce fighting," Gaye said.
An activist in Rastan said fighters of the rebel Free Syrian Army had seized a major checkpoint on the road between the town and Homs.
"The regime's major focus is now on Aleppo, and the FSA in Homs is taking advantage of that," the activist said.
"Now there's only one checkpoint separating our town from the city of Homs," said the activist, who identified himself as Abu Rawan.
Syria's official SANA news agency said troops had "cleansed" the central Qarabis district of Homs of "terrorists."
Observatory director Rami Abdel Rahman said: "Regime forces took control on Sunday night of new sections of the Qarabis district. The regime now controls about 70 percent of the district."
The Observatory says the rebels still control 40 percent of Homs as a whole, including most of the central Old City.