The United Nations says thousands of civilians are trapped in Aleppo, as fighting rages on in the Syrian city.

Forces loyal to the regime of Bashar Al Assad are continuing their offensive against rebel strongholds in the city.

Supplies of food and gas are running low, remaining residents have sought refuge in mosques and schools, while hundreds of thousands have already fled the city.

Meanwhile, footage has emerged – apparently showing the execution of pro-Assad troops by rebel fighters.

However the film has not yet been verified.