More than 30,000 Pakistanis are feared dead and up to 2.5m have been left homeless after the earthquake that struck south Asia at the weekend, according to estimates from aid agencies and government officials.

"We think there are at least 4m very vulnerable people in the affected area, of whom between 1m and 2.5m are severely affected, without a shelter for the night," said Elisabeth Byrs, spokeswoman for the United Nations Office for the Co-ordination of Humanitarian Affairs.