Jamie McGoldrick, U.N. resident coordinator in Kathmandu, told reporters that of those affected 2 million people are in the 11 worst-hit districts.

He says that 72 hours after the quake on Saturday, “people are still in a very much hard-ship mode.”

The challenge of supplying to small villages at high altitudes and in rough terrain “is quite significant, he said.

After flying by helicopter over Dhulikhel town, on the north side of the Kathmandu valley, he estimated that about 40 percent of the houses were damaged, but the destruction was erratic.

“Some areas on one ridge are completely untouched, on the other side it’s completely flattened,” he said.

— Todd Pitman, Kathmandu, Nepal

Read about how authorities are searching for and helping earthquake survivors

GORKHA, Nepal — Helicopters crisscrossed the mountains above a remote district Tuesday near the epicenter of the weekend earthquake in Nepal that killed more than 4,400 people, ferrying the injured to clinics and taking emergency supplies back to villages cut off by landslides.

Around noon, two helicopters brought in eight women from Ranachour village, two of them clutching babies to their breast, and a third heavily pregnant.

“There are many more injured people in my village,” said Sangita Shrestha, who was pregnant and visibly downcast as she got off the helicopter. She was quickly surrounded by Nepalese soldiers and policemen and ushered into a waiting van to be taken to a hospital.

The little town of Gorkha, the district’s administrative and trading center, is being used as a staging post to get rescuers and supplies to those remote communities after Saturday’s magnitude-7.8 quake.

Some women who came off the helicopters were grimacing and crying in pain and unable to walk or speak, in agony three days after being injured in the quake.

Sita Karki winced when soldiers lifted her. Her broken and swollen legs had been tied together with crude wisps of hay twisted into a makeshift splint.

“When the earthquake hit, a wall fell on me and knocked me down,” she said. “My legs are broken.”

After an hour of dark clouds gathering and threatening rain, the wind kicked up in Gorkha and sheets of rain began to pour down.

Geoff Pinnock of the U.N.’s World Food Program was leading a convoy of trucks north toward the worst affected areas when the rain began to pound, leaving them stuck.

“This rain has caused a landslide that has blocked my trucks. I can maybe get one truck through and take a risk driving on the dirt, but I think we’ll have to hold the materials back to try to get them out tomorrow by helicopter,” he said.

Aid workers who had reached the edges of the epicenter described entire villages reduced to rubble.

“In some villages, about 90 percent of the houses have collapsed. They’re just flattened,” said Rebecca McAteer, an American physician who rushed to the quake zone from the distant Nepal hospital where she works.

And yet, the timing of the earthquake — near midday, when most rural people are working in the fields — meant most villagers were spared of injuries when buildings collapsed, she said. So far, police say they have 373 confirmed deaths in Gorkha district.

Most those injured, she added, were young people and the elderly, since most young men long ago left their villages in search of better-paying work.

“The immediate need is getting support to where it’s needed, but there will be a lot of work rebuilding,” said McAteer, who was heading back soon to the center of the quake zone.

Thomas Meier, an engineer with the International Nepal Fellowship who accompanied McAteer to the devastated villages, noted the disaster’s aftermath would stretch long into the future.

“This is a long-term emergency,” he said. “This will need major attention for the next five years. People have nothing left.”

Across central Nepal, including in Kathmandu, the capital, hundreds of thousands of people are still living in the open without clean water or sanitation. It rained heavily in the city Tuesday, forcing people to find shelter wherever they could.

At Kathmandu airport, flights arrived with emergency aid and helicopters brought in both foreign trekkers and local villagers from quake-struck areas. Helicopters chartered by trekking companies reached the Langtang area, about 60 kilometers (40 miles) north of Kathmandu, a popular area for trekking — a key contributor to the country’s economy.

Dave Gordon, from San Francisco, California, said he was in the area until Tuesday waiting for the rescue flight.

“Cliffs came down, four or five porters were deceased, buried in the rock fall,” he said of the quake. “Trails are completely destroyed. People are stuck. They can’t get out. It was very bad.”

The United Nations says it was releasing $15 million from its central emergency response fund for quake victims. The funds will allow international humanitarian groups to scale up operations and provide shelter, water, medical supplies and logistical services, U.N. spokesman Farhan Haq said.

Trucks carrying food were on their way to affected districts outside the hard-hit and densely-populated Kathmandu valley, and distribution of the food was expected to start Tuesday.

Citing government figures, Haq said an estimated 8 million people have been affected by the quake in 39 of Nepal’s districts, and more than 1.4 million need food assistance, including 750,000 who live near the epicenter in poor quality housing.

The U.N. humanitarian country team for Nepal is coordinating international relief efforts with the government and a clearer picture of needs should emerge within the next 48 hours, he said. The immediate priority is search and rescue, and removing debris to find survivors still trapped, he said.

Many of the ornate, historic buildings in Bhaktapur, a key tourist site just east of Kathmandu, were reduced to rubble. Residents began returning to collect whatever belongings they could.

The country’s death toll rose to 4,355, said Deputy Inspector General of Police Komal Singh Bam. Another 61 were killed in neighboring India, and China’s official Xinhua News Agency reported 25 dead in Tibet. At least 18 of the dead were killed at Mount Everest as the quake unleashed an avalanche that buried part of the base camp packed with foreign climbers preparing for summit attempts.

Some 8,063 people have been injured, Bam said. Tens of thousands are believed to be homeless.

Rescue workers and medical teams from at least a dozen countries were helping police and army troops in Kathmandu and surrounding areas, said Maj. Gen. Binod Basnyat, a Nepal army spokesman. Contributions came from large countries like India and China — but also from Nepal’s tiny Himalayan neighbor of Bhutan, which dispatched a medical team.

At the Kathmandu airport, foreign planes from India, the U.S., China, Malaysia, Pakistan, Israel that brought aid and rescue personnel lined up on the crowded tarmac.

Coming out of the airport with dry blood on his face and legs, Min Bahadur Raut said he got a ride on a helicopter from a neighbor who had chartered a flight for his mother. He has not been able to move his left arm.

“We haven’t seen any government help or relief at our village” northeast of Kathmandu, he said. Roads have been closed by landslides. “I don’t know what is wrong with me. I have no money,” he said. “I have been in pain for days now.”

Associated Press writers Todd Pitman and Binaj Gurubacharya in Kathmandu contributed to this report.