Rescue operations in Pakistan and Kashmir are being scaled back as hopes fade of finding anyone alive nearly a week after a devastating earthquake.
The many thousands of homeless urgently need tents and blankets
As thousands of survivors spent a sixth night in the open, a powerful aftershock sent them running into the streets in panic early on Friday.
At least 25,000 people are known to have died, but the UN relief chief says the final figure could exceed 40,000.
Days after the earthquake struck, hundreds of villages remain cut off.
The Pakistani government is planning to set up temporary tent cities to shelter up to two million people estimated to have been left homeless by the quake.
Pakistan's disaster response chief Maj Gen Farooq Javed said it would take many years to rebuild north-east Pakistan, where the earthquake flattened scores of towns and villages.
Maj Farooq Nasir, spokesman for the army's emergency relief operation in Muzaffarabad, capital of Pakistan-administered Kashmir, said it was unlikely anyone else would be found alive under the rubble.
"The technical teams have told us the chance of survival is now less than 2%," he was quoted by AFP news agency as saying.
The BBC's Dumeetha Luthra in Muzaffarabad says search and rescue teams are pulling out of the area to make way for relief to take the priority.
She says help is arriving but the problem is the outlying areas - hundreds of villages have yet to be reached by road or even helicopter.
People are dying from a lack of basic medical care, and wounds that have been untreated for days are turning gangrenous.
Neighbouring India, where at least 1,400 people died in the quake, has sent a second consignment of aid to Pakistan.
On Wednesday, India flew 25 tons of supplies to Pakistan - the first such airlift between the traditionally hostile countries in decades.
'Race against time'
The UN's top humanitarian official Jan Egeland is due to meet Pakistani leaders in Islamabad to discuss relief efforts.
Mr Egeland warned that the final death toll could soar and that time was running out to save survivors.
"I fear we are losing the race against the clock in the [isolated] small villages," Mr Egeland said after touring the disaster areas by helicopter on Thursday.
The Pakistani army has been using helicopters - including 20 lent by the international community - to drop supplies to remote villages.
But our correspondent says there simply are not enough helicopters to cover the scale of the devastation.
Where valleys are too narrow for helicopters to fly, mule-trains are being used to carry food, blankets and tents to quake-hit communities in desperate need before winter sets in.