Fierce bombardment of two opposition-held Syrian towns killed at least 31 civilians including children on Wednesday, the Syrian Observatory for Human Rights monitor said.
Most were killed in air raids likely carried out by either President Bashar al-Assad’s regime or its Russian ally, the Observatory said.
The attacks come despite the army’s extension of a nationwide truce until early Friday. The freeze in fighting has yet to produce any respite in violence.
Bombing raids killed at least 16 civilians and wounded dozens more in the rebel-controlled town of Rastan in central Homs province the Observatory said.
Another three civilians were killed in government shelling on the town earlier in the day.
Rastan -- one of the last rebel strongholds in Homs province -- has suffered a devastating siege by government forces in 2012.
In northwest Syria, 12 civilians including three children were killed in raids on the opposition-held town of Ariha.
The town is controlled by the Army of Conquest, a rebel alliance of mainly Islamist groups including Al-Qaeda affiliate Al-Nusra Front that holds almost all of Idlib province.
An AFP journalist saw civil defence workers using a large bulldozer to clear debris away from a crumbling building.
Some rescue workers wearing face masks used small plastic buckets to clear rubble so they could pull a thin man covered in dust out of a destroyed structure.
“We came to the site of the air strike and there was a huge fire, many corpses, human flesh everywhere,” said Ahmad Qurbay, head of Ariha’s civil defence service.
“The areas that were hit are all residential buildings, near Ariha’s main market,” he added.
Footage uploaded to Facebook by local activists showed men crying over what appeared to be the bodies of victims wrapped in thick, bloodied rugs.
A rescue worker guided one shell-shocked man covered in blood out of a building and into a large ambulance.
Idlib has regularly been targeted by both Syrian government air strikes and raids carried out by its Russian ally.
A longtime backer of the government in Damascus, Moscow stepped up its support for Assad on September 30, when it began an air campaign aimed at bolstering regime positions.
More than 280,000 people have been killed and millions displaced since Syria’s civil war erupted with the brutal repression of anti-government protests in 2011.