At a Red Cross warehouse wrecked by U.S. bombs, Afghans are sifting through the rubble for grains of rice, swinging them back and forth on metal pans to separate the food from the dirt.

They're scrounging for anything useful. "You're shaming us in front of a foreigner," a guard barked at a woman who was digging plastic sheeting from the ruins Saturday. "But I need it!" she cried, saying it would be used for shelter.

While many Afghans have celebrated the collapse of Taliban rule, most people remain mired in abject poverty. The country urgently needs humanitarian assistance as winter approaches, regardless of who rules.

Foreign aid workers kicked out after the Sept. 11 terror attacks on the United States are starting to stream back, but hundreds of thousands of Afghans are at risk of starvation, especially those in mountainous regions where snow blocks access.

"The departure of the Taliban did not bring food and bread," said Alberto Cairo, head of a Red Cross program that aids disabled Afghans.

"I have the impression people are quite happy, hoping for change, but we shouldn't forget that the problems building up for the past 25 years are bigger than ever," he said.

An estimated 4 million Afghans depend on foreign assistance for survival. War, displacement, poverty, human rights abuses and a three-year drought have turned Afghanistan into a humanitarian catastrophe.

The United Nations warns of famine, particularly in the north.

"Winter is a double problem," said Yusef Zai of the United Nations' World Food Program. "People need fuel to warm their houses, but they don't even have food."

Many mountain passes in Afghanistan become iced over in winter, making it difficult or impossible to bring in supplies.

Most aid groups and U.N. humanitarian programs continued after the United States began bombing Taliban forces seeking to force the surrender of Osama bin Laden and members of his al-Qaida network.

The Taliban ordered all foreign aid workers to leave, but local Afghan staffers kept things running and relief supplies kept coming in, although at reduced levels.

"We had staff who weren't willing to work during the U.S. bombing," said Zai, who oversaw the World Food Program in Afghanistan during the international staffers' absence. "We were only using 35, 40 percent of our work force."

After Sept. 11, most international relief groups were not allowed to use their phones, faxes and other communication equipment, at times cutting them off from their headquarters' abroad.

Also shut down after Sept. 11 was the United Nations land mine removal program, which had enjoyed a large degree of success in clearing mines from most roads and other frequented locations. Still, Afghanistan is considered the world's most heavily mined nation.

U.N. international staffers began arriving in Afghanistan on Saturday, and operations that had closed are beginning to reopen.

The end of Taliban rule will likely change the environment for aid work, which was often hindered by the militia's strict religious mandates.

At one point, World Food Program bakeries in Kabul closed briefly because the Taliban wouldn't allow the organization to hire women for a hunger survey.

Last May, an Italian-funded hospital shut in Kabul after Taliban religious police raided it, accusing male and female staff of eating in the same dining room. The Taliban beat and arrested several local staffers.

Three Christian relief groups — Shelter Now, Serve and the International Assistance Mission — were closed down after their members were accused of preaching Christianity. Eight of Shelter Now's foreign staffers and 16 of its local workers were arrested in August and released only this week.

"I think it's going to be much easier now," said Cairo at the Red Cross.

The Canadian Relief Organization, an Islamic group that distributes food, has already hired 10 women — an act forbidden under the Taliban.