Earlier in the capital, snipers fired from buildings. Soldiers shot protesters elsewhere in the country.
Video on YouTube purportedly shows men walking down a street in Damascus carrying guns. Constant gunfire can be heard as well as a man repeatedly saying "Allahu Akbar," or God is great.
CNN is unable to authenticate the footage.
The idea of a cease-fire was met with skepticism immediately after it was floated on Wednesday. Diplomats, experts in the region and rebels predicted that the agreement would fail.
They said Wednesday and Thursday that the effort would just be a repeat of a cease-fire failure in April.
By sunrise Friday, thousands of people poured into the streets across Syria to protest against al-Assad.
Rebel groups reported these additional bouts of violence across the country:
At least three people were killed in tank and sniper fire in a Damascus suburb where government forces have been battling rebel forces on-and-off for control.
Fierce fighting broke out between government forces and the al Qaeda-linked al Nusra Front, which had said earlier it would not abide by the terms of the temporary truce.
The al Nusra fighters laid siege to a military encampment east of the city of Maaret al-Numan.
Government forces shelled a neighborhood in the flashpoint city of Homs where the opposition alleged six rockets fell, wounding two people and damaging a number of buildings. Video of the alleged destruction appeared on YouTube.
At least three people suffered gunshot wounds when Syrian forces fired shots in the air in an attempt to disperse protesters in the town of Inkhil in Dara province.
On the rebel side, a top Free Syrian Army general said Thursday his fighters had agreed to halt military operations if the Syrian government were to do so as well. But he said he doubted that the truce would hold.
Syria's rebel opposition is fractured, and Gen. Mustafa al-Sheikh said that some rebel groups have not agreed to halt operations.
The government, meanwhile, touted its several goodwill efforts Thursday leading to its announcement that it will stop fighting.
State-run TV aired footage of men walking out of a prison -- part of a government amnesty program, a commentator said.
The release came a week after rebel fighters told Al Jazeera news agency that they would agree to a proposed cease-fire only if the government were to release detainees, end a siege in the city of Homs and halt aerial attacks.