KABUL, Afghanistan - Food supplies are rising as aid groups gear up for winter, but banditry on the roads is making it too dangerous to deliver help to many remote areas where millions of hungry Afghans are effectively cut off.

Sixty-nine trucks loaded with wheat rumbled into Kabul yesterday, part of almost daily deliveries for the World Food Program. At one school, the U.N. refugee agency handed out blankets, sweaters and charcoal to some 2,500 impoverished people.

While many in the Afghan capital are hurting, the city's markets are full of food, aid is being distributed, and hospitals are functioning.

The weather in Kabul and in points south is above freezing for now, but snow and cold have already come to the mountainous north.

The most urgent problem is the rugged countryside. Of 6 million Afghans requiring food aid, 4 million are in the "hunger belt" that arcs across the north, including Afghanistan's most isolated pockets.

Even in quiet times, these areas are tough to reach. Winter snows have begun to block roads winding through the Hindu Kush mountains in the northeast, and many paths will soon be impassable. Three years of drought have shriveled local food supplies. Two months of fighting has sent many fleeing their homes.

Aid officials say the greatest single obstacle to delivering supplies is the lack of security on the rutted roads, where robbers and warlords are seizing supplies and preventing aid groups from moving freely.

"I think (road) security at the moment is an issue everywhere," said Burkard Oberle, head of the World Food Program in Afghanistan. "We cannot go very far out of urban areas."

The Red Cross and Medecins Sans Frontieres, two of the largest aid groups operating in Afghanistan, echoed his comments.

The northern alliance, which has captured most of the country from the Taliban, has been unable to secure the roads. The bandits emerged almost immediately after the Taliban fled. Militia leaders, some loosely linked to the northern alliance, and others operating independently, are carving out patches of territory every day.

Even some cities are hard to reach. The World Food Program can't operate in Kandahar, the Taliban stronghold in the south. The U.N. agency planned to return to Mazar-e-Sharif, the largest northern city, but put that effort on hold because of recent fighting and instability.

Aid groups so far haven't been able to send in assessment teams to judge the extent of the shortages in rural areas.

The province of Gor, in the central highlands, was in bad shape before the Sept. 11 terror attacks in the United States that triggered the current crisis and temporarily forced foreign aid workers to leave Afghanistan. The aid groups are still unable to reach Gor due to security problems, and snow could soon make the journey even more hazardous.

"We knew they were way down on food stocks. People were eating their livestock and seeds intended for planting," said Red Cross spokesman Bernard Barrett. "We are very concerned about Gor."

The United Nations has coined a new term for those effectively trapped in mountain villages, labeling them the "internally stuck."

Snow-blocked roads will be a problem in the north for the next several months. Kabul and points south may also get occasional heavy snowstorms, but generally roads in these areas remain passable during winter.

The city of Ghazni has the only full-fledged hospital between Kabul and Kandahar to the south, a distance of 300 miles. Medecins Sans Frontieres has been supporting it, paying the salaries of more than 100 local workers.

The hospital is only 75 miles south of Kabul, but the aid group has not been able to send in international workers because of danger along the road.

"Ghazni is still not secure," said Georges Dutreix, head of the group's mission. "The hospital staff told us not to come for now. They said we must wait for it to cool down."

Another unsafe road is the crucial corridor from the Pakistan border to Kabul. Aid groups have been bringing in trucks with food supplies hauled by Afghan drivers, but aren't sending their workers down the road.

"We're not moving any international staff around on the roads," said Barrett, of the Red Cross. "We put them in by plane and keep them there."

Another frustration for aid workers is the closure of the bridge that crosses the Amu Darya River from Uzbekistan to northern Afghanistan, near Mazar-e-Sharif.

Many needy Afghans in that region are ethnic Uzbeks. Yet President Islam Karimov of Uzbekistan has been reluctant to open the bridge, fearing Afghanistan's chaos could spill into his country.

Even in Kabul, aid distribution is imperfect. Workers for the U.N. High Commissioner for Refugees went door-to-door in a Kabul neighborhood Wednesday, handing out cards to 400 needy families entitling them to pick up supplies at a school yesterday.

But Alleh, a woman who lost her husband and three children when a bomb hit their home in 1996, failed to get a card because she was away from home Wednesday, taking one of her six children to the doctor.

She stood among the crowd outside the school yesterday, unable to pass through the gate to get supplies.

"When I came home yesterday, I found that all the people on my street had a card, but not me," said Alleh.