Desperate earthquake survivors scuffled over relief supplies as the first food convoys reached this devastated city on Tuesday, but the help was far from enough and heavy rains held up some helicopter flights to badly hit areas. An army official said the death toll had climbed to more than 35,000 people. Many bodies were still buried beneath the rubble, and the United Nations warned of the threat of measles, cholera and diarrhea outbreaks among the millions of survivors. The 7.6-magnitude quake on Saturday flattened whole communities, mostly in the Himalayan region of Kashmir, and aid has not reached many areas. "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," the United Nations said in a statement released in Islamabad. The Pakistani government's official death toll was about 23,000 people, but a senior army official involved in the rescue operations said, "according to our assessment, the death toll is between 35,000 to 40,000 people." The official requested anonymity, as he wasn't authorized to comment about it. His estimate matched that of local officials. India said more than 1,400 people died in the part of Kashmir that it controls. India planned to send a planeload of food, tents and medicine to Pakistan, its longtime rival. The nuclear-armed neighbors have fought three wars since independence from British rule in 1947, but have embarked on a peace process. One of the places hardest hit by the quake was Muzaffarabad, the capital of Pakistani-controlled Kashmir, where most homes and all government buildings were destroyed. There is no power or water supply, and many of the city's 600,000 people have no shelter as winter approaches. The nights are already cold. International aid workers, including Turkish doctors, medics from the group â€˜Doctors without Bordersâ€™ and assessment teams from other agencies, were working in the city. But in Muzaffarabad, the effort did not appear to be nearly enough. Bob McKerrow, coordinator of relief efforts for the International Federation of the Red Cross, said in the Pakistani capital of Islamabad late Tuesday that 17 trucks had left for affected areas with supplies, including blood for hospitals. He said heavy rains could hamper the relief effort. "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." About 10 trucks brought by Pakistani charities and volunteers rumbled into Muzaffarabad, where efforts by relief workers to distribute aid turned chaotic as residents scuffled for the handouts of cooking oil, sugar, rice, blankets and tents. Police looked on helplessly as more than 200 people raided a stock of food arranged by relief workers at a soccer field near Muzaffarabad's center _ one of six designated aid distribution points. One man made off with a big sack of sugar, another left on a motorized rickshaw with a big crate of drinking water. "I can't wait for the food to be distributed properly," said Ali Khan, a construction worker who has barely eaten for days. "I need it desperately and I'll take it." The quake damaged sanitation systems in the region, 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," said Fadela Chaib, spokeswoman for the UN's World Health Organization in Geneva. "We fear that if people huddle closely together in temporary shelters and crowded conditions, more measles cases could occur." Measles - potentially deadly for children - are already endemic in the region and only 60 percent of the children are protected. At least 90 percent coverage is needed to prevent an epidemic, WHO said. The agency will soon start gathering essential vaccines for a mass immunization program. The UN World Food Program began a major airlift of emergency supplies. Japan pledged US$20 million in aid, Canada offered US$17 million, and the United States pledged up to US$50 million. Other nations also announced donations of money and supplies, including tents, blankets, medical aid and food kits. Pakistan army spokesman Gen. Shaukat Sultan said a total of 30 helicopters, including eight US military choppers diverted from the war in neighboring Afghanistan, would be supplying food, water, medicine and other items to quake victims. More helicopters from other countries were expected. At least one US military Chinook helicopter was unable to reach the quake zone because of a rainstorm. "We had a storm blow into the area on some of the mountain passes that you have to go through to get into the remote area, and they had to come back and land due to the weather," explained US military spokesman Col. James Yonts. Rescue teams, including Britons, Germans and Turks, used high-tech cameras and lifting gear to search for survivors under piles of concrete, steel and wood. Rescuers pulled a teen-age boy from rubble in the northern town of Balakot on Tuesday, 78 hours after the quake. "He's alive," rescuers shouted with joy. People gave food and water to the boy and kissed him on the head. The area where he was rescued smelled heavily of decomposing corpses. A 55-year-old woman and her 75-year-old mother were also rescued from an apartment building in Islamabad that collapsed in the quake.