Air strikes killed at least 12 civilians including children in two rebel-held neighbourhoods of Syria's divided city of Aleppo on Thursday, a monitoring group said.
Nine people were killed in the Tariq al-Bab area, and another three in the district of Salhin, both in eastern Aleppo, the Syrian Observatory for Human Rights reported.
The Britain-based group said it was unclear whether the strikes were carried out by warplanes of the Syrian government or its ally Russia.
In Tariq al-Bab, civil defence workers sifted through debris for survivors.
"A missile hit... and two whole families lost their lives," said one of them, Mohammed al-Ismael.
"We pulled four martyrs from the rubble, including children and women, and until now there are another six victims under the rubble."
The work proceeded slowly because of ongoing air strikes in the area, each raid forcing the workers to scatter and shelter in nearby buildings.
An older woman sat on the pavement watching the workers dig through the remains of a pancaked building.
"One of my children has been rescued but another one is still underneath the rubble," she told AFP.
Nearby, a distraught Mohamed Qattan dug through debris with his bare hands.
Signup to our newsletter and follow us on Facebook and Twitter!
"My family are beneath the rubble," he said, calling out to them in the hope of hearing a reply.
"I was praying at the mosque when the strike happened. My wife and two of my children -- my son and daughter -- are underneath the rubble," he told AFP.
In Salhin, the strikes also wrought destruction, with video obtained by AFP of the aftermath showing smoke billowing from the front of a multi-storey building shorn of its facade.
The charred skeleton of a car, its windows blown out, sat in front of the building.
Civil defence workers battled a fire sparked by the attack, while civilians with ladders retrieved belongings from the ruins.
"Total destruction," said resident Jomaa Hassan, gesturing to a smoking building behind him.
"These are civilians: a taxi driver, a municipal worker. These are the terrorists in their eyes."
Aleppo city is divided roughly between government control in the west and rebel control in the east.
Last week, government forces advanced to within firing range of the only remaining supply route into the rebel-held east, effectively cutting it off and prompting food shortages and spiralling prices.
The International Committee of the Red Cross said Thursday that 19 trucks loaded with aid entered rebel-held Waer in the central city of Homs, the second such delivery in a month to the regime-besieged district.
More than 280,000 people have been killed in Syria since its conflict began in March 2011 with anti-government protests that were met with a regime crackdown.