MUZAFFARABAD, Pakistan -- Heavy rain and hail grounded helicopters and stopped trucks loaded with relief supplies yesterday, imposing more misery on hungry, shivering earthquake survivors as the United Nations warned of potentially lethal outbreaks of measles, cholera, and diarrhea.
Dazed, desperate villagers fought over food packages and looted trucks as the first aid reached this devastated city in the mountains of Kashmir. The Himalayan region was hit hardest by Saturday's magnitude-7.6 quake.
Officials said the death toll from Pakistan's worst quake had surpassed 35,000, with many bodies still buried beneath piles of concrete, steel, and wood. Millions were left homeless after communities were flattened in the region touching Pakistan, India, and Afghanistan.
Three days after the quake, survivors still were being pulled from the rubble by British, German, French, and Chinese rescue teams. A Red Cross official said people could survive under the rubble up to seven days.
The UN World Food Program began a major airlift of emergency supplies, including high-energy bars to feed 240,000 people.
NATO agreed to coordinate an airlift of aid supplies from Europe. Eight US military helicopters based in neighboring Afghanistan shuttled 16 tons of food, water, medical supplies, and blankets to quake-hit zones, the military said.
Chinook and Black Hawk choppers flew 102 relief workers and others into the region and evacuated 126 people, said Lieutenant Colonel Jerry O'Hara, spokesman for the US base at Bagram, Afghanistan.
In Washington, a Pentagon spokesman said 25 to 30 more military helicopters would be in Pakistan within days. The Islamabad government also requested earthmovers, forklifts, bulldozers, and trucks, spokesman Larry Di Rita said.
The UN appealed for $272 million in donations, saying 2 million people were homeless. The United States pledged $50 million; Japan, $20 million; Canada, $17 million; and Britain, $3.5 million. Other nations donated helicopters, money, and supplies, including tents, blankets, medical aid, and food.
''We as a nation are going through a challenging time," Pakistan's prime minister, Shaukat Aziz, said. ''We are overwhelmed by the support we are getting both within the country and outside the country and are thankful to those countries, friends, and individuals who have made our task easier."
Yesterday's efforts were hampered by torrential rains and hail in the mountains on the Pakistani side of Kashmir, and crates of supplies sat on tarmacs waiting to be delivered. At least one US supply helicopter had to turn around because of a rainstorm in the mountain passes, the military said.
''The recovery efforts have been slowed by bad weather, and large parts of the region are still inaccessible because landslides have destroyed the road network," a UN statement said.
Bob McKerrow, coordinator of relief efforts for the International Federation of the Red Cross, said in Islamabad that 17 trucks left for affected areas with supplies, including blood.
''Some of the roads are just being reopened, and this rain is not going to help at all," McKerrow said. ''And the possibility of further landslides blocking roads is a threat every minute of the day."
The Pakistani government's official death toll was about 23,000, but a senior army official involved in the rescue operations said that ''according to our assessment, the death toll is between 35,000 to 40,000 people." Tens of thousands were injured.
Neighboring India said 1,300 people died in its part of Kashmir, the disputed province at the center of two wars between New Delhi and Islamabad.
India planned to send a planeload of food, tents, and medicine to its longtime rival in what was seen as a boost to the peace process. Islamabad, however, refused India's offer of helicopters.
In Muzaffarabad, the capital of Pakistani-controlled Kashmir, most homes and all government buildings were destroyed and bodies were in the streets. The city had no electricity or running water, and many of its 600,000 people had no shelter with winter just six weeks away. The efforts seemed nowhere near meeting the overwhelming need.
The quake damaged sanitation systems, destroyed hospitals, and left many victims with no access to clean drinking water, making them more vulnerable to disease.
''Measles could potentially become a serious problem," WHO spokeswoman Fadela Chaib said in Geneva. ''We fear that if people huddle closely together in temporary shelters and crowded conditions, more measles cases could occur."