The United States on Monday condemned Syria's ruling regime over the bloody aerial assault on the city of Aleppo, which has left several hundred people dead including dozens of children.
White House spokesman Jay Carney said Washington deplored the attacks on civilian areas by Syrian government forces, accusing the military of using barrel bombs and SCUD missiles "indiscriminately."
"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," Carney said.
"The attacks over the weekend killed more than 300 people, many of them children. The Syrian government must respect its obligations under international humanitarian law to protect the civilian population."
The White House spokesman also called on all parties in the Syrian conflict to "reach a comprehensive and durable political solution to end the crisis in Syria."
Syrian warplanes have killed more than 300 people, including 87 children, in eight days of bombing in Aleppo, just a month before planned peace talks, according to the Syrian Observatory for Human Rights, which relies on a network of activists and witnesses on the ground.
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 others.
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.
Assad's opponents say the bombing is aimed at demoralizing their supporters and turning them against the insurgents.
A security source told AFP the army had adopted the 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, the former commercial hub, has been split between opposition and government forces since a massive rebel assault in July 2012.