Trucks carrying food and medical supplies have begun arriving in the city worst affected by the earthquake that hit northern Pakistan and India.
Muzaffarabad, the capital of Pakistani-administered Kashmir, bore the brunt of Saturday's quake which killed at least 20,000 people.
However, there is anger among survivors over the lack of help from authorities.
Pakistani officials admit they were initially overwhelmed, but say the relief effort is gathering momentum.
Many states have responded to its call for tents, blankets and helicopters.
However, Pakistani Information Minister Sheikh Rashid Ahmed said more was needed.
The US has promised $50m for relief operations and Kuwait pledged $100m.
Eight US helicopters have now arrived in Pakistan from neighbouring Afghanistan.
The US ambassador to Islamabad, Ryan Crocker, said planes with US relief supplies were forming a "virtual air bridge" into Pakistan.
The country has said it will accept aid from India, but has ruled out a joint rescue operation along their frontier dividing the disputed territory of Kashmir.
Pakistan has asked the United Nations to take the lead in co-ordinating the international response, the body's relief co-ordinator says.
Jan Egeland said hundreds of thousands, if not millions, had been left homeless.
"We know that every hour counts in an earthquake of this magnitude," he said.
Rescuers have retrieved a woman and child trapped for more than 60 hours in the rubble of a block of flats in the Pakistani capital, Islamabad.
The country's interior minister said the government had done its best to deliver aid, but the quake had blocked roads and cut communications.
Officials say they now have 20 helicopters engaged in relief and rescue operations.
Pakistani-run Kashmir: At least 17,000 dead
Pakistan's North-West Frontier province: At least 1,600 dead
Islamabad: At least 25 dead
Indian-run Kashmir: At least 950 dead
Some supplies and heavy equipment have reached Muzaffarabad and the flattened town of Balakot in Pakistan's North West Frontier.
But some survivors are angry about the perceived lack of help from the authorities with food and water supplies.
In Muzaffarabad, almost the whole population has spent the past two days in the open, in a city where every second building was destroyed and 11,000 are thought to have died.
The BBC's Aamer Ahmed Khan in the city says people have become more and more desperate, with supply trucks mobbed and reports of looting at damaged shops and homes.
Locals are seething in the Tangdar area in Indian-administered Kashmir, the BBC's Altaf Hussein reports.
Our correspondent says they are angry they have not received rations for three days - from the authorities or non-governmental organisations.
Thousands are spending another cold night in the open air in Balakot, where people spent the day digging in the rubble for survivors.
Hundreds of children's bodies were pulled from the wreckage of schools.
The disaster wiped out a generation of young people in the areas worst hit, a military official has said.
The earthquake, which hit at 0350GMT on Saturday, is thought to have been the strongest the region has seen in a century.
Some reports suggest the death toll may double.