Heavy monsoon showers hit the flood-hit regions of Pakistan on Sunday, worsening the flooding and impeding relief operations, compounding a humanitarian crisis that has affected over 14 million people across the country and claimed nearly 1,700 lives so far.
Floodwaters that have inundated the northwest and central parts of the country raced southward into Sindh province along the Indus river, which officials said was in "exceptionally high flood".
Over 700 villages were flooded as water levels of 1,128,000 cusecs and 1,115,300 cusecs were recorded at the Guddu Barrage and Sukkur Barrage respectively as authorities struggled to cope with the impact of the worst deluge in 80 years.
The protective bunds at Bachal Shah Mayani and Torhi near Sukkur in northern Sindh were breached and several other barrages and embankments were at risk.
Officials said they expected the situation to worsen as heavy rains are forecast to continue in Sindh for the next three days.
With more deaths reported from Khyber-Pakhtunkhwa and Gilgit-Baltistan, the death toll has risen to nearly 1,700.
Tens of thousands of people in Sindh were fleeing the floods but some people resisted evacuation, as they feared their homes would be looted.
"While comprehensive estimates are not yet available, it is certain that hundreds of thousands, if not millions, are being affected in this province," said Dennis Bruhn, a UN disaster management expert in Sindh.
Rivers in other parts of Pakistan too continued to be in spate.
The Kabul River was in "very high flood" at Nowshera in Khyber-Pakhtunkhwa while the Chenab river was in high flood at Qadirabad in Punjab.
The continuing rains caused fresh flooding in Nowshera in the northwest and bad weather grounded helicopter flights for relief missions.
"Things will probably get worse before they start getting better. We are working at full speed to respond to the most urgent needs of the affected populations," said Martin Mogwanja, the UN Humanitarian Coordinator in Pakistan.
The UN said it will be "nearly impossible" to access some of the worst-hit areas for assessments and delivery of aid until the waters recede.
"We are particularly concerned about the needs of 600,000 people who remain completely cut off in the north of Khyber-Pakhtunkhwa especially as no helicopter deliveries have been possible for three days," said Wolfgang Herbinger, Country Director of the World Food Programme.
Prime Minister Yousuf Raza Gilani, who surveyed flooded areas near Sukkur in Sindh by helicopter, appealed for more international aid, saying the crisis had spiralled beyond his government's capacity.
"Whatever we can do within our resources we are doing and will continue to do so. However, the losses are far too stupendous," Gilani said.
Aid workers reported shortages of food, medicine and drinking water.
The World Health Organisation warned that without access to safe water, Pakistanis were at high risk of contracting waterborne diseases like diarrhoea and cholera.
While the amount of funds required for relief operations cannot be known until needs are assessed, the UN said it expected the amount needed over the coming months will be several hundreds of millions of dollars.
"With so much destruction to agricultural land and to infrastructure, more hundreds of millions, if not billions, will be required on the longer term to restore livelihoods and services including the health system," said Ahmed Shaboul, the WHO's officer-in-charge for the country.
The floods are the worst witnessed in Pakistan since 1929. The province worst affected is Khyber-Pakhtunkhwa, where an estimated 1.5 million people are homeless.
UN agencies have distributed health kits and medicines and launched emergency services like restoration of clean drinking water to check epidemics among people marooned in flood-affected areas.
The health equipment includes cholera kits, emergency kits, surgical supply kits and anti-snake venom.
There were also reports of protests by people who complained that the government had failed to provide them much-needed items like food and clean water.
At Jampur in Punjab, a large number of people gathered outside government offices to protest.They threw stones at officials and shouted slogans against the government.