The crisis has been generated by the harshest winter in memory, followed by a drought across much of the country, which come on top of the broader problems of deteriorating security, the accumulated pressure of returning refugees and the effects of rising world food prices. The failure of the Afghan government and foreign donors to develop the country's main economic sector, agriculture, has compounded the problems, the officials say. They warn that the food crisis could make an already bad security situation worse.

The British charity Oxfam, which conducted a provisional assessment of conditions in the province of Daykondi, one of the most remote areas of central Afghanistan, has appealed for international assistance before winter sets in. “Time is running out to avert a humanitarian crisis,” it said.

That assessment is echoed by villagers across the broader region, including in Bamian Province. “In all these 30 years of war, we have not had it as bad as this,” said Said Muhammad, a 60-year-old farmer who lives in Yakowlang, in Bamian. “We don't have enough food for the winter. We will have to go to the towns to look for work.”

Underlying the warnings are growing fears of civil unrest. The mood in the country is darkening amid increasing economic hardship, worsening disorder and a growing disaffection with the government, particularly over the issue of government corruption.

Returning refugees are already converging on the cities because they cannot manage in the countryside, and they make easy recruits for the Taliban or other groups that want to create instability, said Hashmat Ghani, an opposition politician and tribal leader from Logar Province, south of Kabul, the nation’s capital.