The number of people suffering from the massive floods in Pakistan now exceeds 13 million - more than the combined total of the 2004 Indian Ocean tsunami, the 2005 Kashmir earthquake and the 2010 Haiti earthquake, the United Nations has said.
The death toll in each of those three disasters was much higher than the 1,500 people killed so far in the floods that first hit Pakistan two weeks ago. But the UN estimates that 13.8 million people have been affected - over two million more than the other disasters combined.
The crisis, which is believed to be the worst in Pakistan's history, has overwhelmed the government, generating widespread anger from flood victims who have complained that aid is not reaching them quickly enough or at all.
Many of the people affected by the floods, which were caused by extremely heavy monsoon rains, were in Pakistan's north-western province of Khyber Pakhtunkhwa.
Rescue workers have been unable to reach up to 600,000 people marooned in the province's Swat Valley, where many residents were still trying to recover from last year's fight with the Taliban. Bad weather has prevented helicopters from flying to the area, which is inaccessible by ground.
Hundreds of thousands of people have also had to flee rising floodwaters in recent days in the central and southern provinces of Punjab and Sindh as heavy rains continued to pound parts of the country.
One affected resident, Manzoor Ahmed, said that although he managed to escape floods that submerged villages and destroyed homes in Sindh, the total lack of government help meant dying may have been a better alternative.
"It would have been better if we had died in the floods as our current miserable life is much more painful," said Ahmed, who fled with his family from the town of Shikarpur and spent the night shivering in the rain that has continued to lash the country.
"It is very painful to see our people living without food and shelter," he said.
The disaster could also have serious repercussions for Pakistani President Asif Ali Zardari, who has been criticised for going through with a planned trip to France and Britain despite the devastating floods at home.