Thousands of people were heading back into the city of Thatta after frantic efforts by Pakistani troops and volunteers saved the historic community from surging floodwaters.

Across Pakistan's inundated southern province of Sindh, officials said that more than a month after torrential rains in the northwest triggered unprecedented flooding, waters were starting to recede. While the threat of the waters would remain for several days, they were hopeful that the worst may be over.

While parts of the town of Sujawal, on the other side of the Indus River, become flooded on Sunday, officials in Thatta said emergency levees that had to be repeatedly plugged with mud and stones for several days had held firm and that water had shifted direction.

About 300,000 people had been evacuated from the city, famed for several monuments listed as World Heritage Sites, such as the Jama mosque, lined with glazed tiles, which was built by the Mughal ruler Shah Jahan in the 17th century.

"The breach near Thatta has been half-plugged and fortunately the flood has also changed its course and is moving away from the city and populated areas," said a city official, Hadi Bakhsh Kalhoro. "The water is flowing into the sea and its level is receding, and many people are returning."

High tides in the Arabian Sea have dropped, finally allowing the Indus to start discharging. Meteorologists have predicted that it could take another 10 to 12 days for the province's rivers to return to their normal levels.

As people start shifting back to their homes, aid groups say there is a pressing need for emergency supplies of food, drinking water and medicine. From across Pakistan's flood zones there have been reports of increasingly angry and frustrated people struggling to get their hands on basic supplies. Often what is given is thrown to them from the backs of passing aid trucks, which often triggers fights and scuffles. Women and the elderly often suffer when supplies are distributed in such a way.

In Sindh, where 19 of its 23 districts were inundated by brown floodwater, as elsewhere in the country, the spectre haunting the affected is the spread of disease. With up to 17 million people affected, the country will be left with an enormous relief and reconstruction programme that could take years to complete and cost billions of dollars.

While over the weekend Muslim countries, organisations and individuals pledged about $1.4 billion in relief supplies and donations, many officials fear that Pakistan will still lack the funds necessary to recover from the worst natural disaster in its history.

US Senator John Kerry yesterday added his voice to those who have said more international aid was needed for Pakistan to counter political instability and extremism.

"The danger of the floods extends beyond a very real humanitarian crisis," Kerry wrote in the International Herald Tribune.

"Pakistan has made enormous strides in combating extremism and terrorism - at great sacrifice.

"But its ability to keep up the fight requires an effective response to this crisis."