With snow falling on parts of Kashmir (search), the U.N.'s emergency relief chief said Thursday that time was running out for many hungry, homeless survivors of a massive earthquake and urged aid agencies to speed up efforts in remote villages.

The plea came as aid workers struggled to reach remote areas and hours after an aftershock jolted parts of Pakistan (search), panicking people who had survived last weekend's devastating temblor and forcing a rescue team to suspend efforts to save a trapped woman. She died before the rescuers returned to the precarious rubble.

U.N. Undersecretary General and Emergency Relief Coordinator Jan Egeland (search) flew by helicopter to the hard-hit Kashmiri city of Muzaffarabad (search), where he said there was an urgent need to get food, medicine, shelter and blankets to millions of people. The U.N. estimates 2 million people are homeless ahead of the fierce winter in the Himalayan region.

The death toll was believed to be more than 35,000 and tens of thousands were injured. India has reported more than 1,350 deaths in the part of Kashmir that it controls.

"I fear we are losing the race against the clock in the small villages" cut off by blocked roads, Egeland said. "I've never seen such devastation before. We are in the sixth day of operation, and every day the scale of devastation is getting wider."

The U.S. military in Afghanistan loaded cargo planes with food, tarpaulins and other emergency aid to drop by parachute over areas of Pakistan, officials said. The first plane was expected to leave Friday morning loaded with 10 tons of aid, said U.S. military Sgt. 1st Class Rick Scavetta.

Trucks with aid from dozens of countries choked the roads up to the crumbling towns of Kashmir, but access to some areas remained blocked because of landslides and people in many remote areas where there are no roads were still in desperate straits five days after the temblor struck.

Underscoring the difficulty, ActionAid International in Pakistan said some of its workers had to get out of their truck and walk in one area because of bad roads and traffic jams.

"The problem is that people are facing a shortage of time," said Shafqat Munir, a spokesman for the group. "It's cold, raining. People are without shelter. They have food, clothes, blankets, but tents are a problem."

The 5.6-magnitude aftershock was centered 85 miles north of Islamabad, near the epicenter of Saturday's 7.6-magnitude quake that demolished whole towns, mostly in Kashmir and northwestern Pakistan. The aftershock shook buildings, but no significant damage in the already demolished region was reported.

"There was a lot of panic. People were scared. Even those who were sleeping in tents came out. Everybody was crying," said Nisar Abbasi, 36, an accountant camping on the lawn of his destroyed home in Muzaffarabad, the capital of Pakistan-controlled Kashmir.

Carrying water, juice and milk, a relief team from Britain-based Plan International flew in a helicopter to villages in northern Mansehra district in North West Frontier Province and found scenes of death and desperation.

"The whole valley is smelling awfully," said Dr. Irfan Ahmed, the aid group's health adviser. "People were hungry and panicking. We organized them and gave charge to the people there so they could distribute according to needs."

He said it rained and already started to snow on Wednesday, with winter just five weeks away.

"Conditions are going from bad to worse. These people don't have any shelter. Also the school has collapsed, and the children were in those classrooms," he said.

Ahmed said he saw one elderly survivor evacuated with a semiconscious 3-year-old boy who was barely moving, his skin cold and clammy.

A 22-year-old woman trapped in the rubble in Muzaffarabad died Thursday after the aftershock disrupted efforts to rescue her, rescuers and witnesses said.

British, German and Turkish teams had worked until 2 a.m., trying to extract the woman after a sniffer dog detected her in the debris. But they were forced to suspend their efforts amid fears for their own safety when the aftershock shifted the building in which they were working.

When the rescuers returned after daybreak, the sniffer dog whined, indicating that it had detected the smell of a corpse. Some rescue workers wept.

"It was a very difficult decision to leave a living person and I had a responsibility to my team. It could have meant their death," said Steff Hopkins, a British team leader.

Dozens of aftershocks have occurred since the main quake, including a 6.2-magnitude temblor.

"They will go on for months, possibly years," said Don Blakeman, geophysicist at the U.S. Geological Survey's National Earthquake Information Center.

In Muzaffarabad, meanwhile, relief workers wrapped 35 bodies in shrouds and carried out a mass burial on Thursday. The burial was coordinated by Jamat-e-Dawad, a group linked to Islamic militants that is operating dozens of ambulances in the city and running a camp for quake victims. The group has hundreds of volunteers, who wear white headbands.

Hope of finding survivors dwindled in Muzaffarabad, where Britain's Department for International Development was pulling out its team of 60 search and rescue workers, said Rob Holden, the team leader for U.N. disaster assessment and coordination, which is overseeing the overall rescue effort.

"No one is giving up but it is the acceptance that the actual real chances of finding someone alive are almost nil, so we don't need all the specialist international teams," Holden said, adding that 18 international teams are still in the region.

German, Afghan, Pakistani and U.S. helicopters delivered tents, blankets and medical equipment and brought back dozens of badly injured people on each return flight.

The United Nations estimated some 4 million people were affected, including 2 million who lost homes, and warned that measles and other diseases could break out.

Earlier this week, the U.N. launched an international appeal for $272 million for six months of emergency aid to Pakistan. Some 30 nations have contributed relief supplies and manpower but Egeland said he believes countries should provide more help.

"We have seen a much graver picture and I believe we need to triple the number of helicopters in the operation. My appeal to the world is to come up with more aid, more relief, and more resources," he said.

Egeland said he thought the initial response was "not bad," given the difficulties of blocked roads and rain.

"Tens of thousands of tents, hundreds of thousands of tons of emergency food, a million blankets and other relief goods are in the pipeline," he said.