BEIRUT - Syrian warplanes have killed more than 300 people, including 87 children, in an eight-day bombing campaign in the second city of Aleppo a month before planned peace talks.
The vicious air campaign has seen regime aircraft drop barrels of TNT onto rebel-held neighborhoods -- a tactic widely condemned as unlawful -- flooding hospitals with victims, according to activists, medics and other witnesses.
The attacks come as President Bashar al-Assad's forces have advanced on several fronts in recent weeks while Western nations have been preoccupied with Syria's chemical disarmament and preparing for January peace talks.
"From December 15 to 22, 301 people have been killed, including 87 children, 30 women and 30 rebels," said the Syrian Observatory for Human Rights, a Britain-based group which relies on a network of activists and witnesses on the ground.
It added later that five more people, including three children, were killed in a new attack on the district of Marjeh, in southeastern Aleppo.
Activists released what they said was footage of a school targeted in the village of Marea near Aleppo. Children can be seen running from the school and screaming as loud 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.
Opponents of Syrian President Bashar al-Assad say the bombing is aimed at demoralizing their supporters and turning them against the insurgents.
A security source told AFP on Monday that the army had adopted the tactic because of a lack of ground forces, and argued that the heavy civilian toll was because the rebels -- branded "terrorists" by the regime -- are based in residential areas.
Aleppo, the country's second city and former commercial hub, has been split between opposition and government forces since a massive rebel assault in the summer of 2012.
Human Rights Watch has accused government forces of using weapons and tactics that fail to distinguish between civilians and combatants, making such attacks "unlawful.”
On Sunday the main opposition National Coalition called on Western states to impose a no-fly zone to halt such attacks.
"Until Assad's warplanes are stopped, the humanitarian disaster, regional instability and the rise of extremism will only continue to get worse," said Munzer Aqbiq, an adviser to the Coalition's president.
The government has advanced on several fronts in recent weeks in an apparent attempt to strengthen its hand ahead of peace talks to be held in Switzerland next month.
The UN-backed initiative is aimed at building on the momentum of a deal to eradicate Syria's vast chemical arsenal by mid-2014, which averted punitive US strikes after an August gas attack near Damascus killed hundreds of people.
But analysts argue US President Barack Obama's failure to act after Assad allegedly crossed his "red line" against using chemical weapons has emboldened the regime, while the chemical arms accord has made Assad a vital partner in his own disarmament.
"There are no more red lines, there is a green light," Salman Shaikh, the director of the Brookings Doha Center, told AFP, saying there is an "element of vengeance" in the fierce bombing of Aleppo.
"Any credible of use of force was taken off the table by Obama and the international community."
The so-called Geneva 2 talks are intended to get the government and the opposition to agree on a political transition to end the civil war, which has claimed an estimated 126,000 lives since March 2011 and displaced millions of people.
But the increasingly fractured opposition has said Assad must step down as part of any deal, a demand rejected by Damascus.
And several powerful rebel groups have rejected the peace talks altogether, raising concerns that even if the two sides reach an agreement the opposition would be unable to enforce it on the ground.
Syria's uprising began as a series of peaceful pro-democracy protests nearly three years ago but escalated into a full-blown civil war after Assad's regime launched a brutal crackdown on dissent.