Nepal's prime minister has declared three days of national mourning for the victims of Saturday's devastating earthquake which has left at least 4,700 people dead.

Rescue operations continued on Tuesday, with helicopters ferrying the injured and delivering emergency supplies to remote villages near the epicentre.

PM Sushil Koirala also thanked donors in a televised address to the nation.

He had earlier warned that the number of people killed in the country's worst earthquake in decades could reach 10,000.

With the UN estimating eight million people have been hit by the disaster, Koirala said getting help to some of the worst affected areas was a "major challenge".

He said authorities were overwhelmed by appeals for help from remote Himalayan villages left devastated by the 7.8-magnitude earthquake.

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

"In some villages, about 90 percent of the houses have collapsed. They're just flattened," said Rebecca McAteer, a US physician who went to the earthquake zone from the distant Nepal hospital where she works.

Two rescue helicopters on Tuesday reached Ranachour village, in Gorkha district, evacuating eight women, two of them clutching babies, and a third heavily pregnant, to the nearby town of Gorkha. 

"There are many more injured people in my village," said Sangita Shrestha, who was pregnant and visibly downcast as she got off the helicopter. 

In Barpak, further north, rescue helicopters were unable to find a place to land. On Tuesday, soldiers had started to make their way overland, first by bus, then by foot.

Helicopters dropped food packets in the hope that survivors could gather them up.

Meanwhile, an avalanche struck a village on Tuesday in Rasuwa district, a popular trekking area to the north of Kathmandu.

Uddhav Bhattarai, the district governor, said up to 250 people were missing.

Infographic: Indian plate UPDATED [Al Jazeera]

The government has yet to assess the full scale of the damage.

Laxmi Prasad Dhakal, home ministry spokesperson, said the official death toll had risen to about 4,700, with more than 9,000 known to have been injured.

In places like Kathmandu's Basantapur Durbar Square, rescue teams were scrambling to clear the debris to find bodies and possibly survivors trapped underneath.

Heavy rain in the capital was hampering rescue efforts and also adding to the suffering of those made homeless by the earthquake or sleeping out in the open in fear of aftershocks.

Al Jazeera's Annette Ekin, reporting from Kathmandu, said many locals were camping out in Nandakishore Park, in central Kathmandu, huddling under blankets.

But despite the loss of life and property around them, most people remained calm.

"There's no one they can blame for this, so people are in pretty good spirits," she said. "Some musicians are camped out in the park, playing the guitar."

Many spent the night in tents, returning only briefly to their homes to pick up supplies.

Speaking to Al Jazeera, Dr Deepak Prakash Mahara,  a senior consultant and an orthopaedic surgeon at Tribhuvan University Teaching Hospital, said: "Quite a significant number of patients are still lying in our yellow zone area, awaiting for the operations to be done."

The yellow zone is for patients who do not have life-threatening trauma, but need surgeries.

The hospital has received almost 400 victims of the earthquake, 138 of them are still awaiting surgeries, reported Ekin.

International support

The UN says it is releasing $15m from its central emergency response fund for the quake victims.

The funds will allow international humanitarian groups to scale up operations and provide shelter, water, medical supplies and logistical services, UN spokesman, Farhan Haq, said.

INSIDE STORY: What caused Nepal earthquake?

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

The size of the capital's airport is a major hurdle to bring in aid, as only planes of a certain size can land on the single runway.

In Kathmandu, hospitals were working non-stop, running dangerously low on blood.

Youths were volunteering in hospitals and also as first-aid responders and to clear debris.

Outside of Nepal, 73 people died in India. The toll in China's far western region of Tibet, which neighbours Nepal, rose to 25, the official Xinhua news agency said, citing the area's disaster relief headquarters.

 

Source: Al Jazeera and agencies