GENEVA/NEW YORK (REUTERS) - Donors have pledged more than a billion US dollars to help Afghanistan, where poverty and hunger have spiralled since the Islamist Taliban took power, and foreign aid has dried up, raising the spectre of a mass exodus.

UN Secretary-General Antonio Guterres said it was impossible to say how much of the money had been promised in response to an emergency UN appeal for US$606 million (S$813.29 million) to meet the most pressing needs of a country in crisis.

After decades of war and suffering, Afghans are facing "perhaps their most perilous hour", he said in his opening remarks to a donor conference in Geneva.

"The people of Afghanistan are facing the collapse of an entire country - all at once." He said food supplies could run out by the end of this month, and the World Food Programme said 14 million people were on the brink of starvation.

The Taliban ruled Afghanistan according to their strict interpretation of Islamic law from 1996-2001 and were toppled in an invasion led by the United States, which accused them of sheltering militants behind the Sept 11 attacks.

They swept back to power last month in a lightning advance as the last US-led Nato troops pulled out and the forces of the Western-backed government melted away.

With billions of dollars of aid flows abruptly ending due to Western antipathy and distrust towards the Taliban, several speakers in Geneva said donors had a "moral obligation" to keep helping Afghans after a 20-year engagement.

Neighbours China and Pakistan have already offered help.

Human rights concerns

But UN human rights chief Michelle Bachelet, also in Geneva, underlined the Western misgivings. She accused the Taliban of breaking recent promises by once more ordering women to stay at home rather than go to work, keeping teenage girls out of school, and persecuting former opponents.

Beijing announced last week it would send US$31 million worth of food and health supplies. Iran said it had dispatched an air cargo of humanitarian aid.

Pakistan sent supplies such as cooking oil and medicine, and called for the unfreezing of Afghan assets held abroad.

"Past mistakes must not be repeated. The Afghan people must not be abandoned," said Pakistani Foreign Minister Shah Mehmood Qureshi, whose country has close relations with the Taliban and would most likely bear the brunt of an exodus of refugees.

The United States pledged nearly US$64 million in new humanitarian assistance at the conference, while Norway pledged an extra US$11.5 million.

Even before the Taliban's seizure of Kabul last month, half the population - or 18 million people - depended on aid. That looks set to increase due to drought and shortages.

About a third of the US$606 million being sought would be used by the UN World Food Programme, which found that 93 per cent of the 1,600 Afghans it surveyed in August and September were not getting enough to eat.

"Brink of starvation"

WFP Executive Director David Beasley told the conference that 40 per cent of Afghanistan's wheat crop had been lost, the cost of cooking oil had doubled, and most people anyway had no way of getting cash to buy food.

While Afghanistan's banks have started reopening, the queues for withdrawals are endless, and more importantly, no one who depended on the government for a salary - from civil servants to police - has been paid since July.

"Fourteen million people, one out of three, are marching to the brink of starvation. They don't know where their next meal is," he said.

"If we are not very careful, we could truly, truly enter into the abyss in catastrophic conditions, worse than what we see now." The World Health Organisation, another UN agency that is part of the appeal, is seeking to shore up hundreds of health facilities at risk of closure after donors backed out.

UN High Commissioner for Refugees Filippo Grandi warned that there could be far greater displacement soon than the estimated half a million who have already sought refuge elsewhere in Afghanistan this year.

"I fear that the collapse of services and of the economy that has already been described as a risk coupled perhaps with increased violence and tension could lead to a much greater displacement - internal and external - and this may happen very soon," he told the conference from Kabul.

"The physical distance between our nations and Afghanistan shouldn't mislead us," Turkish Foreign Minister Mevlut Cavusoglu added.

"A humanitarian and security crisis in Afghanistan will have direct implications across the globe. We should take collective action now."