A three-year drought had already caused problems

Seven thousand Afghans made their way back home from Iran last week alone, according to the UNHCR.

"The returning refugees have told our staff there that they are very hopeful for their future in Afghanistan," said a spokeswoman for the organisation, Maki Shinohara.

They are returning as the UN puts a cost of $9bn of rebuilding the country over the next five years.

The figure is a "preliminary estimate", stressed UN Development Program administrator Mark Malloch-Brown at the end of a two-day international conference in Brussels.

It includes a goal of $2-3bn to be unleashed over the next 30 months to get 1.5m Afghan children back to school, create 100,000 "work-for-food" jobs and provide running water to about 15,000 households.

The bitter Afghan winter has now begun and the narrow window of opportunity is shrinking by the day

Save the Children co-ordinator

But a British charity has warned that Afghanistan is also desperate for short-term aid, without which up to 100,000 of its children could die this winter.

Save the Children, which is running a special appeal for Afghan children, stressed that their predicament pre-dated the current military operation. Years of civil war, three years of drought and punishing winters have all taken their toll.

"The bitter Afghan winter has now begun and the narrow window of opportunity is shrinking by the day," said the charity's health co-ordinator, Ascencion Martinez.

"Most of those forced from their homes by drought or conflict are left with nothing over their heads except the thin cloth of a makeshift tent, and their families will die from cold, hunger and disease if we cannot reach them quickly enough."

Aid at risk

The new international force for Afghanistan will be powerless to protect aid convoys delivering supplies across the country.

The force will be stationed in Kabul but security in the rest of the country is out of their control.

The executive director of the World Food Programme, Catherine Bertini, said there were still major cities which could not be reached because of security concerns - although six main supply routes from neighbouring countries were now open and considered reliable.

Major aid donors at their meeting in Brussels this week have warned Afghanistan's warlords that aid will only be forthcoming if they ensure the country's stability.