The Syrian army exchanged fire with rebels in battleground second city Aleppo even before the expiry at midnight on Wednesday of a Russian- and US-brokered ceasefire.
Two people were wounded early Wednesday when regime aircraft strafed rebel positions in two eastern neighbourhoods of the divided city with heavy machinegun fire, an AFP correspondent reported.
Late Tuesday, government warplanes struck two other rebel-held neighbourhoods, the correspondent added.
Rebel rocket fire hit two government-controlled neighbourhoods in the west of the city, the Syrian Observatory for Human Rights said.
Rebel sniper fire killed one person late Tuesday, the state SANA news agency reported.
A local truce took effect in Aleppo last Thursday after a surge in fighting in the city killed more than 300 people and threatened to unravel a nationwide ceasefire between government forces and non-jihadist rebels in force since February.
The truce has led to a sharp reduction in the death toll. Rebel rocket fire on government neighbourhoods killed three civilians on Sunday but otherwise it has largely held.
It has been extended twice after 11th-hour diplomatic intervention by the major powers but there was no immediate word of any new extension ahead of Wednesday's expiry time.
Moscow and Washington pledged on Monday to redouble efforts to shore up the nationwide truce and reach a political settlement to the conflict which has killed more than 270,000 people in Syria since 2011.