DAMASCUS - Syrian warplanes have killed more than 330 people in a nine-day bombing campaign, with the US condemning the "indiscriminate" assault and the opposition National Coalition saying it will not attend planned peace talks if it continues.
The vicious campaign has seen aircraft drop barrels of TNT on rebel-held neighbourhoods in Aleppo - a tactic widely condemned as unlawful - flooding hospitals with victims, according to activists, medics and others.
The Syrian Observatory for Human Rights, which relies on a network of activists and witnesses on the ground, said Monday that 331 people had been killed since December 15, including 99 children.
It said 30 of the victims died Monday in attacks on the rebel-held Marjeh and Soukkari districts of Aleppo, once Syria's commercial capital.
Activists released footage of what they said was a school targeted in the village of Marea near Aleppo.
Children can be seen running from the school and screaming as explosions rumble in the background.
Inside, men pull children from the rubble, their faces caked in dust and blood. It was not possible to verify the footage.
A security source told AFP President Bashar al-Assad's army had adopted the barrel-bombing tactic because of a lack of ground forces, and argued the heavy civilian toll was because the rebels - branded "terrorists" by the regime - are based in residential areas.
Aleppo has been split between opposition and government forces since a massive rebel assault in July 2012.
The White House lashed out at the Assad regime for the bombings.
"The United States condemns the ongoing air assault by Syrian government forces on civilians, including the indiscriminate use of SCUD missiles and barrel bombs in and around Aleppo over the last week," said White House spokesman Jay Carney.
Human Rights Watch has accused government forces of using weapons and tactics that fail to distinguish between civilians and combatants, making such strikes "unlawful".
The main opposition National Coalition called on Western states to impose a no-fly zone to halt the attacks, saying they were creating a humanitarian catastrophe and fuelling extremism.
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