A UN official said Monday that the Pakistani floods have affected more people than the Indian Ocean tsunami did in 2004.
'In terms of people affected, this flood is worse than the tsunami,' Maurizio Giuliano, a spokesman for the UN Office for the Coordination of Humanitarian Affairs (OCHA), told DPA.
'Our assessment is based on figures provided by the NDMA (National Disaster Management Authority) - 13.8 million affected - that is more than the people affected in the tsunami. The people affected by the tsunami were five million,' he said in a telephone interview. 'Out of 13.8 million, not all are severely affected but most of them are.'
The floods triggered by heavy monsoon rains submerged villages, washed away bridges and killed over 1,600 people in the northwestern province of Khyber-Pakhtunkhwa last week.
The water then devastated large areas in the central province of Punjab and caused havoc in the southern province of Sindh.
'It is a looming human disaster. We do not know as yet but in the short term it will need hundreds of millions of dollars and in the long term it will be billions of dollars,' Giuliano said.
The statement came as efforts to airlift aid to flood victims in Khyber-Pakhtunkhwa had to be halted due to bad weather Monday as tens of thousands of refugees faced food shortages.
'Around 40 military helicopters were taking part in the rescue and relief operation but we have halted the flights because of rain,' an army spokesman said. Six US helicopters flown in from Afghanistan for the relief efforts were also grounded.
Landslides triggered by fresh rainfall blocked several roads and floods washed away more bridges in Khyber-Pakhtunkhwa province.
The situation in the province's Malkand region was deteriorating further as hundreds of villages and hamlets were isolated.
With the helicopters grounded and surging water making movement by boat difficult, the aid workers were using donkeys and mules to transport relief items.
'We are facing here a severe shortage of food items,' said Shehzad Alam, a resident of Mingora, the main town in Swat district. 'Most of the food reserves are destroyed and what is left at the markets is so expensive that it is beyond the purchasing power of the ordinary man.'
'Roads are closed and grocery items do not get here from other cities,' Shehzad said by phone. 'The situation is even worse in small villages where people are starving now, particularly in some parts of Shangla (district).'
A spokesman for the World Food Programme said that in areas like those it was a 'race against time and the support of the donor community will be critical to save people.' Around 4.5 million people would need food supplies for at least three months,' Amjad Jamal said.
The UN estimated that more than 600,000 hectares of crops were destroyed in Punjab, the country's breadbasket. Farmers in Khyber-Pakhtunkhwa have lost 35 billion rupees ($408 million) worth of crops, the state-run newswire APP cited a government report as saying.
Dozens of people have died in new floods in Khyber-Pakhtunkhwa as the meteorological department predicted at least one more day of monsoon rain.
In the central and southern provinces of Punjab and Sindh, authorities were evacuating more people from low-lying areas along the Indus River. Some two million people have so far been moved to safer areas.
Water flow in the Indus has risen above 31,000 cubic meters per second, 10 times more than the normal level.