Saturday's airstrike slammed into a marketplace in the Tariq al-Bab neighborhood, said the Aleppo Media Center activist group and the Britain-based Syrian Observatory for Human Rights.
The Observatory, which relies on a network of activists on the ground, said 25 people, including four children, were killed and dozens were wounded in the strike. The Aleppo Media Center published a list of 21 names of people it said were killed in the air raid. The discrepancy could not be immediately reconciled, but differing death tolls are common in the chaotic aftermath of such attacks.
An activist with the Aleppo Media Center, Hassoun Abu Faisal, said the airstrike took place around 10 a.m. local time when the market was packed with shoppers.
"Cars were damaged, debris and rubble are everywhere," he said via Skype. "Many of the wounded have lost limbs."
One amateur video posted online showed scenes of carnage: a body, its legs twister under it, lying in a pool of blood in front of a smashed car; the body of another man ripped in half in the middle of the street; men rushing a limp body past shattered storefronts. In another video, blankets cover at least three bodies on a sidewalk. Muddy black shoes poke out from under one of the blankets. The videos appeared genuine and corresponded to other AP reporting of the events depicted.
Both Abu Faisal and the Observatory reported airstrikes in other opposition-held areas of Aleppo, including Myassar, although there was no immediate word on casualties.
Aleppo, Syria's largest city, has been a major front in the country's civil war since rebels launched an offensive there in mid-2012. The city has been heavily damaged since then in fighting that has left it divided into rebel- and government-controlled areas.
Another critical battleground is around the capital of Damascus. Assad's forces have a tight grip on the heart of the city, but many of the suburbs have been opposition strongholds since the early days of the uprising.
In a grueling campaign that has lasted months, government forces have managed to capture some of the rebel-held towns and villages ringing Damascus, while others have held out despite daily shelling.
One such town is Moadamiyeh, which activists say has been strangled by a government siege for nearly a year. Assad's troops have set up checkpoints around the community west of Damascus and have barred entry of food, clean water and fuel in a bid to pressure residents to expel rebels from the town.
The blockade has had a devastating effect on those stuck inside. For months, activists in Moadamiyeh have warned that malnutrition is rife among the town's estimated 8,000 civilians. They say at least two women and four children have died of hunger-related illnesses in September.
This week, residents reached a deal with the army that would see the town receive food in exchange for raising the government flag over Moadamiyeh. The agreement also demanded rebels hand over their heavy weapons and that only registered residents may remain in the town.
Locals hoisted the flag above Moadamiyeh Thursday. Late Saturday afternoon, three small pickups entered with bread, rice and canned food, said Moadamiyeh-based activist Qusai Zakarya.
"It's very, very small shipment. We have over 8,000 civilians. They have brought in around three tons of food," he said. "This amount of food won't be enough for 1,000 civilians for one day."
He said residents want the government to allow large, continuous shipments of food such as flour, rice and canned goods, so the town can store the items in case the supply line is cut.
He alleged the government agreed to the deal in order to improve its image ahead of peace talks expected next month in Switzerland, but said it would only send small shipments so that it can maintain its hold over Moadamiyeh.