The United Nations is still waiting to deliver aid to the besieged Syrian city of Aleppo, four days after a ceasefire came into effect.

At least 250,000 people are in desperate need of food and medicine, but the UN says the Syrian government has failed to provide permits to trucks into rebel-held east Aleppo.

The BBC's Middle East editor Jeremy Bowen reports from a university campus in government-controlled west Aleppo.