Islamabad, Aug 26 (IANS) Pakistan ordered nearly half a million people to evacuate three towns in Sindh province Thursday as rising floods threatened further havoc in the southern part of the country.

In the province of Sindh, where the floods have washed away huge swathes of rich farmland on which Pakistan’s economy depends, a senior administration official warned that fresh floods threaten three towns.

‘We have warned people of Sujawal, Mirpur Bathoro and Daro towns to leave for safer places in view of possible flooding there,’ Geo TV quoted Hadi Bakhsh Kalhoro, the senior official in Thatta district, as saying.

‘Sujawal, Mirpur Bathoro and Daro towns have an approximate population of 400,000,’ he said.

Kalhoro said the warning was issued after floods caused a breach in one of the embankments at Surjani village in Thatta, close to the Indus river.

The country’s worst natural disaster has killed over 1,600 people and affected about 20 million nationwide, with the threat of disease ever-present in the camps sheltering survivors.

The UN warned that 800,000 people in desperate need of aid had been cut off by the deluge across the country and appealed for more helicopters to deliver supplies to those people reachable only by air.

Authorities were also battling Thursday to save the city of Shahdadkot from surging waters after most of its 100,000 residents had been moved to safety.

Rescuers safely evacuated 90 percent of people from the nearby flooded town of Qubo Saeed Khan. However, efforts were being made to rescue thousands of others stranded in at least 25 villages surrounding the town.

Tens of thousands of people have been evacuated from flood-threatened areas close to Hyderabad city, on the lower reaches of the Indus, where more than 40 nearby villages have been swept away.

US officials say they have encountered no hostilities in flying aid to stricken parts of Pakistan, where anti-American sentiments run deep.

In Kotri, a western suburb of Hyderabad, the Indus river had swollen from its normal width of 200 to 300 metres to almost 3.5 km, according to a local army spokesman.

But a senior engineer at Kotri barrage said that the water level was steady. ‘We are expecting it to start receding from tonight.’