MUZAFFARABAD, Pakistan - Trucks of aid arrived in the ruined capital of Pakistan-ruled Kashmir on Tuesday and victims scuffled for badly needed food and blankets three days after a devastating earthquake flattened whole communities, killing tens of thousands and leaving millions homeless.

U.S. military helicopters helped ferry wounded people from the wrecked city of Muzaffarabad, while international rescue teams joined searches during the waning days of hope for finding survivors. A French team reportedly rescued 40 children from a buried school in another northern town late Monday.

Pakistan's government officially put the death toll at just over 20,000, but local officials estimated it could be twice as high. With winter just six weeks away, the United Nations said 2.5 million people in the worst-hit areas near the mountainous Pakistan-India border need shelter.

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.

It was the first major influx of aid since the monster 7.6-magnitude quake struck Saturday morning, destroying most homes and all government buildings in this city, and leaving its 600,000 people without power or water. Most have spent three cold nights without shelter.

Two or three 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.

''Relief activity has started on a massive level,'' said deputy city commissioner Masood-ur Rehman. He said two army brigades would start clearing roads and debris in the city on Tuesday.

The U.N. World Food Program began a major airlift of emergency supplies. Japan pledged US$20 million (euro16.5 million) in aid, Canada US$17 million (euro14 million), after some criticism at home that its initial pledge was too small. The United States on Monday offered up to US$50 million (euro41 million).

Pakistan army spokesman Gen. Shaukat Sultan said a total of 30 helicopters, including eight U.S. military choppers diverted from the war in neighboring Afghanistan, would be supplying food, water, medicine and other items to quake victims. Two more German and four Afghan helicopters would arrive later Tuesday, he said.

Even long-time rival India planned to send a planeload of food, tents and medicine after Pakistan set aside its often-bitter rivalry with its nuclear neighbor and said that it would accept New Delhi's aid. However, Islamabad has declined an offer of Indian helicopters.

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.

In the small northern town of Balakot, where at least three schools crumbled in the quake, Pakistani troops aided by French experts on Monday rescued 40 children and retrieved 60 bodies from one of the schools, a Pakistani television station and a military official said.

Sajid Awan, a resident, said workers resumed their search early Tuesday and had pulled out more bodies, and were trying to reach buried classrooms where more children might still be alive.

In North West Frontier Province, at least 3,500 people have died and more than 8,500 are injured, and many areas have yet to be reached by rescue teams, an official of the crisis management office said. But he said that about 10,000-12,000 people may have died according to unconfirmed reports.

''We know that several villages in Mansehra district were completely wiped out, and many among the dead were schoolchildren,'' said the official, who didn't want to be named because he is not authorized to speak to the media.

On Pakistan's side of the militarized border in divided Kashmir, senior officials estimate the toll at between 25,000 and 30,000.

On the Indian side, the toll rose Tuesday to 1,005.

President Gen. Pervez Musharraf said his government was doing its best to respond to the crisis.

''We are doing whatever is humanly possible,'' Musharraf said. ''There should not be any blame game. We are trying to reach all those areas where people need our help.''

In Muzaffarabad, a doctor, Iqbal Khan, said survivors were at risk for diarrhea and pneumonia if drinking water and other supplies did not arrive quickly.

In the Pakistani capital of Islamabad, rescuers continued digging through the ruins of a 10-story apartment building after pulling a woman and child to safety. Asim Shafik, who was assisting in rescue efforts, said voices were heard in the rubble, where at least two dozen people died.