Aid workers cut short relief efforts Thursday as their helicopters ran out of fuel, forcing hundreds of earthquake victims in northern Afghanistan to spend another night without food.

Pounding rains gave way to clear skies, allowing four small helicopters to resume flights and evacuate villagers injured five days earlier in the 6.9-magnitude quake. Nearly 5,000 people were believed to have been killed.But a much-needed supply of aircraft fuel never made it to Fais-a-bad's airstrip, requiring the helicopters to return to Dushanbe airport in neighboring Tajikistan to refuel rather than continue their deliveries of grain and vegetable oil to devastated villages.

"We were expecting the fuel yesterday," said Rupert Colville, a U.N. spokesman. "The helicopters could have worked for several more hours today. That means a lot more people will go hungry tonight who didn't have to."

As many as 10,000 people could be facing serious food shortages, he added.

The World Food Program has managed to get 1.5 tons of wheat, vegetable oil and high-protein biscuits by helicopter to remote Shari Basurkh - a devastated village close to the quake's epicenter.

But dwindling food stocks were forcing some villagers to cook and eat grass.

The extent of the damage from Saturday's quake remained unclear, with helicopter crews locating devastated villages that hadn't appeared previously on aid agencies' maps.

From helicopters, aid workers could see entire villages that had been flattened - some buried under landslides and others sent tumbling into valleys below.

In the village of Regi, perched on a peak at the end of a deep valley, about half of its 110 houses had been destroyed.

In Rustaq, dozens of men used horses and donkeys to dig out from the debris 140 schoolchildren killed in the quake. Here - the site of an earlier quake in February that killed 2,300 people - U.N. aid workers set up bakeries to feed people. The nearest clean water was 12 miles away after landslides buried the villages' fresh spring.

Three powerful aftershocks rocked the area on Wednesday.

As one temblor struck, aid workers said villagers dropped to their knees in prayer and refused to enter their damaged houses to salvage belongings or food for fear of being caught in more aftershocks.

Despite heavy rainstorms, thousands of people slept outdoors while waiting for supplies and medical attention Wednesday.

To make matters worse, the downpours increased the need for emergency tents and plastic sheeting, but forced several aid flights to return to Pakistan still laden with supplies.