Residents and rebel fighters in besieged areas of eastern Aleppo are due to start evacuating after the government took full control of the city, although their departure has reportedly been delayed.

A Syrian rebel official told Reuters news agency that pro-Damascus Shi'ite militias were obstructing the evacuation.

The British-based Syrian Observatory for Human Rights also said the planned evacuation had been delayed but it said it was not clear why.

A witness told Reuters that 20 buses were parked with their engines running on a main road out of the city, awaiting the evacuees, with another dozen counted nearby, but it appears that so far no-one had boarded the vehicles.

ITV News correspondent Dan Rivers said earlier that "small arms fire" could be heard near the supposed evacuation point but it had stopped.

ITV News editor Jonathan Wald said there were no government or Red Cross officials overseeing the evacuation as might be expected.

Reuters reported that on Tuesday sources gave different expected start times for the evacuation.

Opposition officials said they had expected a first group of wounded people to leave on Tuesday evening.

A military official in the pro-Assad alliance had said the evacuation was due to start at 5 am local time (0300 GMT).