BHAKTAPUR, Nepal — Rescuers struggled to reach Nepal's more rural communities on Monday to assess the damage from a devastating earthquake that has left more than 3,800 people dead.
The 7.8-magnitude earthquake struck Saturday, killing thousands and flattening centuries-old buildings in the capital city of Kathmandu. The temblor also sparked a deadly avalanche on Mount Everest.
Kathmandu residents were continuing to sleep outside following two days of powerful aftershocks. The official death toll jumped above 3,800 on Monday, with more than 7,100 others injured, according to Nepal's National Emergency Operation Center. Aid agencies warned that figure could leap higher once rescuers make it to isolated rural communities.
"Villages in the areas affected near the epicenter are literally perched on the sides of large mountain faces and are made from simple stone and rock construction," Matt Darvas, a Nepal-based worker with the Christian charity World Vision, said in a statement from the group.
Darvas said such villages are "routinely affected" by landslides and that it's not uncommon for entire village of 200, 300 or even 1,000 people to be "completely buried" by rock falls.
"We are slowly hearing reports that this may have been the case in villages in the Kaski and Gorkha regions," he added.
The International Organization for Migration said on Twitter that aerial and satellite surveillance showed "whole towns" had been flattened.
Many of those small towns and villages were located in a mountainous, agricultural region home to more than 2 million people, said World Food Program spokeswoman Elisabeth Byrs. She said that without access to these areas it was "impossible to give real estimates or to assess the real scale of the disaster."
Around eight miles from Kathmandu in the ancient city of Bhaktapur, funeral pyres burned as groups of women wailed and mourned the dead.
Many buildings inside the town were damaged, with armed police working to dig people out of collapsed structures. Ganesh Pradhan was watching as police dug through the rubble of his home.
"This is my house. I ran out without thinking to rescue myself," he told NBC News. "I thought that was a natural instinct. I lost my 21-year-old son now they're trying to dig out my mother-in-law — but she's dead."
As the death toll mounted, authorities were struggling over a lack of food, water and medical supplies. UNICEF said some 940,000 children were living in areas severely affected by the earthquake and that the children were particularly vulnerable to waterborne diseases.
With their homes either destroyed, or fearful of more aftershocks, around 30,000 people were living in makeshift shelters in government-provided camps, according to the British charity Oxfam.
The charity said that damage to roads and infrastructure was making it extremely difficult to reach out to communities outside the Nepalese capital.
"At the moment, all the death count reports are coming from Kathmandu Valley. Sadly, I fear that this is only the beginning," Oxfam's Nepal Director Cecilia Keizer said in a statement.
The top official for Gorkha district — where the quake had its epicenter — said his region was in desperate need of help.
"Things are really bad in the district, especially in remote mountain villages," Udav Prashad Timalsina told The Associated Press by telephone. "I have had reports of villages where 70 percent of the houses have been destroyed."
Around 90 percent of Nepal's 100,000-soldier army was helping with the rescue operation, spokesman Jagdish Pokhrel told the AP.
As international organizations warned of urgent aid needs, some of the aircraft carrying much-needed supplies from overseas were forced to turn back because of congestion on the tarmac at Kathmandu's airport.
India's Defense Ministry spokesman Sitanshu Kar on Twitter that two planes carrying communications equipment, water and personnel were forced to turn back to India.
In Kathmandu, men and women dug through the rubble with their bare hands to search for survivors and bodies.
Sarella Tiwari told NBC News she "used to hang out" with her friend at the very spot where she was now digging.
"I am worried that there are people down there," Sarella Tiwari told NBC News from atop a rubble pile. "They are my people, you know…we just got to help them. I am not digging out because they are my friends, I am digging out because they are my people."
The long-term economic cost of the earthquake could exceed $5 billion — around 20 percent of Nepal's GDP — according to global consultancy firm IHS, which said in a statement Monday that the impact on the country's economy would be "devastating."
Richard Engel reported from Kathmandu and Alexander Smith reported from London. NBC News' Laura Saravia, The Associated Press, and Reuters contributed to this report.