Nowshera, Pakistan – Rescuers trying to reach thousands of Pakistani flood victims were hampered by deluged roads and damaged bridges Saturday, while fears of disease rose as some evacuees showed signs of diarrhea, fever and other illnesses.

Floods killed more than 430 people in a week, left some 400,000 people stranded in far-flung villages and severely damaged the nation's already-weak infrastructure. The U.N.

estimated Saturday that some 1 million people were affected, though it didn't specify exactly what that meant.

In the northwest, the hardest-hit region, it was the worst flooding since 1929. People clung to fences and each other as water gushed over their heads, TV footage showed. Scores of men, women and children sat on roofs.

 "There are very bad conditions," said Amjad Ali, a rescue worker in the Nowshera area.

"They have no water, no food."

A doctor treating evacuees at a small relief camp in Nowshera said some had diarrhea and others had marks appearing on their skin, causing itching. Children and the elderly seemed to have the most problems, Mehmood Jaa said.

"Due to the floodwater, they now have pain in their bodies and they are suffering from fever and cough," Jaa told The Associated Press.Rescuers were using army helicopters, heavy trucks and boats to try reaching flood-hit areas, the U.N. said. It reported that thousands of homes and roads were destroyed, and at least 45 bridges across the northwest were damaged.

The destruction is slowing the rescue effort, said Luther Rehman, a government official in Khyber-Pakhtoonkhwa, the northwest province. Floodwaters were receding in some areas there, he said.

 "Our priority is to transport flood-affected people to safer places. We are carrying out this rescue operation despite limited resources," he said, adding they needed more helicopters and boats.

The flooding capped an already deadly week in Pakistan. A passenger jet slammed into hills overlooking Islamabad killing all 152 people on board Wednesday, and bad weather is suspected to have played a role.