Earthquake survivors in Nepal's mountain villages plead for help, as U.N. officials say more helicopters are needed to reach the isolated areas. 

At the entrance of this destroyed mountain village stands a wooden sign cobbled together from the debris of homes flattened by Nepal's devastating earthquake. Its message: "WE NEED HELP. PLEASE HELP."

A steep winding road leads up to the ruins of the small village of Pauwathok, perched on a ridge about 3,600 feet above sea level. It's just 30 miles east of Kathmandu, Nepal's capital. But villagers say not one government official, not one soldier has visited since the massive quake struck a week ago, underscoring just how unprepared and overwhelmed Nepal's government has been.

Early Saturday, a convoy of covered trucks approached Pauwathok. The trucks were apparently transporting aid and escorted by Nepalese police carrying automatic weapons. Hungry residents ran toward the road.

The trucks did not stop.

"Are we invisible to you?!" a voice among the crowd screamed as the trucks rode slowly up a hill and out of sight.

One week after the strongest tremor to hit impoverished Nepal in eight decades, aid has been slow in reaching those who need it most. In many places it has not come at all.

U.N. humanitarian officials said Saturday that they were increasingly worried about the spread of disease. They said more helicopters were needed to reach isolated mountain villages like Pauwathok, which were hard to access even before the quake.

Rescuers have found three survivors in a mountainous village in Nepal, several days since the earthquake, an official said Sunday.

Two men and a woman had been pulled from the rubble near Syauli village earlier this week, government administrator Surya Prasad Upadhaya said Sunday.

It was not immediately clear which day they were found.

An initial Associated Press report on the survivors misinterpreted the statement about the time of the rescue.

They have been taken to a nearby military hospital for treatment, Upadhaya said.

The district is the worst hit by the magnitude-7.8 earthquake with the highest number of casualties.

It is located about 35 miles west of the capital, Kathmandu.

The true extent of the damage from the earthquake is still unknown as reports keep filtering in from remote areas, some of which remain entirely cut off. The U.N. says the quake affected 8.1 million people -- more than a quarter of Nepal's 28 million people.

The government said Sunday that the quake had killed 7,040 people. 

Nepal has been shaken by more than 70 aftershocks following the April 25 quake, and its people remain on edge. One brief aftershock Saturday afternoon shook Pauwathok's only paved road, triggering screams from residents who began to run, then stopped when the tremor eased.

The small village is located in the district of Sindupalchok, where more deaths have been recorded than anywhere else in Nepal -- 2,560, compared to 1,622 in Kathmandu. The U.N. says up to 90 percent of the houses in Sindupalchok have been destroyed.

Only a handful of the village's roughly 80 homes remain habitable. Mostly made of brick and mud and sticks, they were either completely leveled or damaged beyond repair. Some families now sleep under makeshift shelters of debris that they constructed from their own ruined homes -- torn roofs and boards, whatever was left.

Others sleep under tarpaulins -- obtained only after residents sat in the middle of the road Friday and blocked an aid convoy that eventually relinquished 30 of them, said Giri, who took one for his family. "We only have the clothes on our backs. The rest has been buried under the rubble," he said.

Volunteers have begun stepping into the void. Late Saturday, Pauwathok's appeal for help was finally answered.

A truck full of rice, noodles and medical supplies pulled up. Everyone crowded round.

The truck had been organized by a teacher who went for help to Kathmandu, where he collected donations from charities and friends.

"The government has not been able to cater to the needs of everyone, so it's better if everybody can pitch in," said Supral Raj Joshi, who helped bring the aid. "It's not that the government isn't trying, it's that they've not been able to reach everywhere."

Six other civilians, several of whom worked with street kids in Kathmandu, also came to deliver medical aid Saturday.

While the situation in Pauwathok is grave, some remote parts of Nepal have suffered far more.

David O'Neill of U.K. International Search and Rescue said a team from his group had driven as far as it could, then walked for hours into six remote villages to assess them. The team reported that the villages had been so badly hit, 80 percent of their inhabitants had died.

"Everything has been flattened," O'Neill said. The people there apparently died not in the original quake, but in a major aftershock the next day, he said.

O'Neill spoke in Chautara, a destroyed town in Sindhupalchok. His team had hoped to reach the remote areas by helicopter, but none were available, so they were returning to Kathmandu.

"The earthquake has caused unimaginable destruction," said Rownak Khan, a U.N. Children's Fund senior official in Nepal. "Hospitals are overflowing, water is scarce, bodies are still buried under the rubble and people are still sleeping in the open. This is a perfect breeding ground for disease."

Medicine, medical equipment, tents and water supplies are needed now, he said.

"We have a small window of time to put in place measures that will keep earthquake-affected children safe from infectious disease outbreaks -- a danger that would be exacerbated by the wet and muddy conditions brought on with the rains," Khan said.

In Jalkeni, a village not far from Pauwathok, the road is lined with mounds of broken wood and stone, the remains of destroyed homes.

On top of one mound sat a woman cradling a young girl. The mound -- surrounded by a pile of dusty rocks, a broken TV and shredded clothes -- used to be Sunita Shrestha's two-story home.

"No one has come to help us yet," said Shrestha, as the sun beat down. "I don't know if they ever will."

The Associated Press contributed to this report.