PRINCES RISBOROUGH, UNITED KINGDOM - AUGUST 5: Britain's Prime Minister David Cameron, greets Pakistan's President Asif Ali Zardari as they meet on August 5, 2010 at Chequers near Princes Risborough in England. President Zardari has come under fire for his diplomatic visit to the UK whilst over 1,100 people have been killed by devastating floods in his country.
An aerial photograph from an Army helicopter shows the flooded town of Sanawa, located in the Muzaffar Ghar district of Pakistan's Punjab province August 5, 2010. So far, the floods have killed more than 1,600 people and officials said the toll was likely to climb. More than 4 million have also lost their livelihoods and homes. Flood victim Fazal Nihar tries to empty mud from his shop after returning to Charsadda, located in Pakistan's northwest Khyber-Pakhtunkhwa province August 5, 2010. Pakistan's biggest floods in 80 years threaten to inflict widespread suffering in Sindh province after the unpopular government failed millions of people ravaged by the disaster in other parts of the country.
The United Nations rushed a top envoy to Pakistan to mobilise international support and address the urgent plight of more than 4.2 million affected by torrential monsoon rains across the volatile country that have killed around 1,500.
The disaster is now into its second week and the rains are spreading into Pakistan's most populous provinces of Punjab and Sindh, as anger mounts against the government response after villages and farmland were washed away.
In Sindh, authorities warned that major floods were expected on Saturday and Sunday in fertile agricultural areas along the Indus river.
The military said 25,000 people had been evacuated in parts of the province while the local government put the number at 150,000.
"We have a target evacuation of at least 500,000 people who live in 11 most vulnerable districts," said provincial irrigation minister Jam Saifullah Dharejo, saying many towns and villages were in danger.
Maurizio Giuliano, a spokesman for the UN Office for the Co-ordination of Humanitarian Affairs (OCHA), said rising water levels could pose a threat to Sukkur Barrage.
Officials warned that dams could burst as heavy rain lashed the Punjab town of Kot Addu, transforming the area into a giant lake.
"All these villages are dangerous now. We are evacuating the population. Important installations are in danger," said Manzoor Sarwar, police chief for Muzaffargarh district.
Survivors criticised authorities for failing to come to their rescue and provide better relief, piling pressure on a cash-strapped administration straining to contain Taliban violence and an economic crisis.
"Everybody is leaving. We came out empty-handed. We didn't have enough time to take our belongings," Ghulam Mustafa, 26, said in Mehmood Kot, a village about six hours' drive south of Lahore, the capital of Punjab.
Houses, shops, petrol pumps and small villages were submerged. Villagers waded barefoot through water up to their necks and chests, carrying belongings on their heads.
"There's up to six feet (1.8 metres) of water in the city. All our stuff was destroyed. We saved only our children," Sadaqat Ali, 28, a plumber from Kot Addu said.