Afghan President Hamid Karzai has warned that instability in Afghanistan poses a huge threat to peace and prosperity in the whole region.
The UN has put out urgent calls for donations
Mr Karzai's blunt message came at a conference in India where he urged neighbouring nations to continue and boost their help for his country.
"The job is not over and the stakes are still very high," Mr Karzai said.
The UN World Food Programme has warned it cannot feed millions of Afghans who will depend on it during the winter.
The meeting in Delhi, attended by representatives from Pakistan, Iran and several other countries, is aimed at improving Afghanistan's economy by involving its neighbours in reconstruction.
But opening the conference, Mr Karzai said extremism and violence by militant groups remained a fearsome challenge five years after his government began rebuilding Afghanistan.
"The security of the region and the world at large are not yet fully safeguarded," he said.
"We ... recognise that Afghanistan's stability is an asset for this region whereas unstable Afghanistan will undoubtedly put the vision of a peaceful and prosperous region in serious jeopardy," he said.
"Today there are a host of other factors - from fragility of security to inadequate physical infrastructure to inconsistent policies which play to the detriment to the regional economic cooperation."
He added that if the economy were more developed, there would be less support for the Taleban insurgency and fewer farmers would turn to the booming opium trade.
Mr Karzai called on countries to invest in key area like agriculture and the electricity system, and to examine new ways of sharing the region's water resources.
The BBC's Simon Watts says that while this conference may provide some assistance to Kabul, delegates know that the lack of security compounds all the country's problems.
In an interview for the Guardian newspaper, UN Afghan mission head Tom Koenigs said Nato forces could not defeat Taleban militants on their own but would have to win people over with good governance and the help of the new Afghan army.
Nato troops have been battling Taleban forces in the south
Mr Koenigs said Nato was being "very optimistic" but urged the alliance to stop doing things on its own.
"You have to win people over. And that is done with good governance, decent police, diplomacy with Pakistan and development," the Guardian quoted him as saying.
Nato-led forces have faced fierce resistance from Taleban militants in the south of the country in recent months.
Civilians make up a quarter of the 4,000 people killed this year in the insurgency, which has been concentrated in the areas worst affected by the drought.
'Lives at risk'
World Food Programme officials said on Friday that they had received only a third of the funds it requested to feed more than three million Afghans this winter, and any extra money would be too late for those in need.
A further three million Afghans not covered by the WFP are also threatened by food shortages, the WFP says, while almost two million people have been affected by drought which has wiped out much of the wheat crop in the south and west.
WFP Asia spokesman Paul Risley told the BBC they were worried that Afghanistan was slipping down the international agenda.
"It may be what some of the experts like to call donor burnout, where they're concerned that after the end of the Taleban rule in Afghanistan that now Afghanistan should be able to take on many of these problems on its own."