Authorities in Pakistan are battling to save the city of Shahdadkot in the flood-devastated southern province of Sindh.
Following a mass evacuation order, most of the city's 100,000 residents have been escorted to safety.
The near month-long floods have killed 1,500 people and affected up to 20m nationwide.
Tens of thousands of people have been evacuated from flood-threatened areas in the south, including from Shahdadkot.
'We are right now trying to protect Shahdadkot ... which is threatened by the rising floodwaters,' Sindh provincial irrigation minister Jam Saifullah Dharejo told AFP.
He said an embankment built to protect the city was under pressure from the waters and 'we are trying to save the city from the unprecedented flood'.
'But there are still some people stranded in these villages (around Shahdadkot) and we are making efforts to rescue them,' he said.
Pakistan's government has faced an outpouring of fury over sluggish relief efforts, while officials warn the country faces ruinous economic losses.
Millions of survivors are in desperate need of food, shelter and clean drinking water and require humanitarian assistance to survive, as concerns grow over potential cholera, typhoid and hepatitis outbreaks.
Up to 500,000 people are living in about 5,000 schools in flood-hit areas where poor hygiene and sanitation, along with cramped quarters and stifling heat, provide fertile ground for potentially fatal diseases.
The International Monetary Fund has said it will review Pakistan's budget and economic prospects in light of the disaster.
The meetings in Washington will focus on a $10bn IMF programme agreed in 2008, and the budget and macro-economic prospects will be reviewed because of the magnitude of the flood disaster.
