Rebels and troops clashed in the Damascus district of Qadam on Wednesday as at least 52 people were killed in violence around Syria, the Syrian Observatory for Human Rights said.
Apart from the fighting in Qadam, hundreds of youths gathered late Tuesday in the capital's upmarket district of Mazzeh and chanted anti-regime slogans, it said.
Troops continued to pound rebel-held areas of the central province of Homs, the Observatory said, noting that shelling was especially violent in the besieged areas of Jurat al-Shiah and Qarabees.
The watchdog also reported violent shelling in the rebel-held town of Rastan, also in Homs, causing widespread destruction.
An amateur video posted on YouTube on Wednesday by anti-regime activists showed the impact of shelling on Rastan.
"This school and this house were pounded," said Abu Rawan, a citizen journalist in Rastan who shot a series of interviews with women and children in the besieged town.
When troops shelled Rastan Wednesday morning, "we hid in the bathroom. I was very scared," a young boy tells Abu Rawan.
A second video shows Rastan's market, much of it destroyed, the streets filled with rubble. Still, some continue to buy and sell vegetables.
"It's a kind of challenge against destruction," activist Abu Rawan is heard saying. "The people just want to live."
Of those killed on Wednesday, 23 were civilians, 18 soldiers and 11 rebels, the Observatory said.
The watchdog reported 82 deaths on Tuesday.
According to estimates from the group, more than 17,000 people have been killed since the uprising erupted in mid-March last year, at first with peaceful protests.
It is not possible to independently verify death tolls since the United Nations stopped compiling such figures at the end of 2011.