Pakistan flood surge moving south

Emergency crews are still trying to assist people in flood-ravaged northwestern Pakistan, while officials are warning people in the south to brace for floods and an outbreak of disease that may follow.

The floods have already killed an estimated 1,500 people over the past week, and as many as four million people have been affected by the floods, which tore through villages, swallowed homes and destroyed crops.

"It is a catastrophe, there'sreally no other word for it," Joseph Prior, a field co-ordinator for Doctors Without Borders, told CBC News.

Much of the damage was concentrated in the country's northwest, which has not seen such devastating floods since 1929.

Aid workers and government officials have struggled to deliver aid as water and mud devastated local infrastructure.

Four U.S. army helicopters arrived in the area Thursday to help transport people who had been stranded by the floods. A U.S. Embassy spokesman told The Associated Press that 800 people werelifted outand relief goods distributed.

Manuel Bessler, the United Nations humanitarian chief in Pakistan, told reporters "we are facing a disaster of major proportions."

"Even a week after the disaster we don't have all the details. Roads are washed away. Bridges are destroyed. Whole areas are completely isolated and only accessible by air."

Floods spreading south

Meanwhile, authorities have issued flood warnings for Punjab province in Pakistan's east and Sindh province in the south, where rivers were swelling to dangerous levels.

In Sindh, some 150 points along the Indus River were considered especially vulnerable.A report released Tuesday by the UN office for humanitarian affairs suggests that Sindh province is "bracing for the biggest floods in 34 years."

Khair Muhammed Kalwar, director of operations at Sindh's Provincial Disaster Management Authority, told IRIN news that operations to evacuate people from vulnerable low-lying areas are underway.

Flood waters have already torn through parts of Punjab, Pakistan's most populous province, where the army used boats and helicopters to move people to higher ground.

"We are migrants in our home," said Ahmad Bakhsh, 56, who fled Sanawan, a town now under water. "Oh God, why have you done this?"

Floods damage crops

The flooding has also damaged infrastructure and caused extensive crop damage, officials said, prompting concerns about food shortages.

The World Food Program said Wednesday that it is scaling up food relief efforts in hard-hit parts of northwestern Pakistan.

WFP executive director Josette Sheeran said the agency hoped to reach more than 250,000 people in need of food aid by the end of the week.

"We are prioritizing the worst-affected areas. More distributions are due to start as WFP mobilizes staff to overcome immense logistical challenges," she said.

Sheeran said the WFP has struggled to get to many remote communities because flood waters destroyed bridges and washed out roads. The WFP fears that as much as 80 per cent of the country's grain stocks have already been washed away.

Once the initial flood danger has subsided, officials worry about an outbreak of water-borne disease.

"For the moment, it's just normal diseases, nothing to worry about,"Prior said.

"The big fear is water-borne diseases which come from the fact that people dont have anypotable water, so they are forced to drink water from the river which might be potentially infectious. We are worried about a big epidemic of cholera," he said.

The Pakistani government response to the floods has been criticized, especially because President Asif Ali Zardari left for a visit to Europe soon after the crisis began.