BBC's Alan Little follows one of the first helicopters delivering supplies to Northern Afghanistan (2'06")

United Nations officials say the aftershocks caused some panic although the extent of any damage is not yet known.

Food supplies have started to reach survivors

Food supplies are beginning to reach survivors most of whom have not eaten since the first earthquake struck on Saturday.

They are living in makeshift shelters that offer little protection.

Even those whose houses remain standing are prevented from returning home because of the threat of further aftershocks.

Many villages can be reached only by helicopter

The United Nations has issued an urgent appeal for helicopters and fuel to help survivors. But torrential rain and a lack of transport are slowing the relief effort.

And aid workers said they could not distribute the 20 sacks of wheat that came from the European Community because it was such a small amount and they felt it might cause a riot.

BBC Correspondent Richard Galpin sees first aid arriving at a remote village

The International Red Cross spokesman in Afghanistan, Juan Martinez, said he hoped that more helicopters would arrive in the area soon. He said they are urgently needed for speeding up the relief operation - as many villages still have not been reached at all.

Damage 'worse than expected'

The earthquake - which measured up to 7.1 on the Richter scale - struck around the towns of Rostaq and Faizabad in an area close to the border with Tajikistan.

An estimated 4,000 people were killed in the earthquake, which aid workers say damaged a much wider area than first thought.

Villages flattened by the quake

Villages have been completely flattened, with houses shaken off mountainsides and sent crashing into the valleys.

Relief workers say it was fortunate that the earthquake struck during the day when many people would have been outside their homes.