Airstrikes pummel Aleppo as Syria launches offensive

Massive airstrikes rained down on the Syrian city of Aleppo once again on Friday as the army declared an offensive against rebel-held areas.

The Russian-backed Syrian army sent the warplanes over the country's biggest city, in attacks which have so far left at least 27 dead. A ceasefire that provided a rest from hostilities broke down on Monday.

Reuters reports that 250,000 people are still trapped in the opposition-held sector of Aleppo, and the army has given no indication that the airstrikes will stop any time soon.

Russia supports Bashar al-Assad's government, while the United States has backed the opposition in the conflict.

Aleppo was once the commercial capital of Syria, but has been ravaged by the bitter dispute which has killed an estimated 400,000.

The city is a key battleground in the war, with the government maintaining control of the western half, and the rebels mostly controlling the east.

Head of the civil defense rescue service in the rebel area, Ammar al Selmo, told Reuters the scene was one of "annihilation".

"What's happening now is annihilation in every sense of the word," he said. "Today the bombardment is more violent, with a larger number of planes."

Last week's ceasefire was thought to provide better access to humanitarian aid, but collapsed before an aid convoy was hit in an attack on Wednesday.