Aid workers describe devastation from Pakistan floods

The United Nations made an urgent plea for helicopters as the death toll from weeks of massive flooding in Pakistan neared 1,600 people Wednesday.

"We need at least 40 additional heavy-lift helicopters, working at full capacity, to reach the huge numbers of increasingly desperate people with life-saving relief," Marcus Prior of the World Food Programme said in a statement.

Flood waters have washed away critical roads and bridges throughout the country, but especially in the mountainous areas of Gilgit Baltistan and Pakistani-administered Kashmir, and in the Swat Valley of Khyber Pakhtunkhwa province.

"In northern areas that are cut off, markets are short of vital supplies, and prices are rising sharply. People are in need of food staples to survive."

The United Nation's estimates that 800,000 people in need of humanitarian aid across Pakistan are only accessible by air.

Over three weeks, Pakistan's floods have affected more than 17 million people, leaving some 4 million homeless. An estimated six million people are in need of emergency shelter, of which just over 1 million have received tents or plastic tarps.

The death toll from the flooding in Pakistan rose to 1,589 Wednesday, according to the nation's Disaster Authority.

Adding to the misery, the forecast calls for more monsoon rains across upper Pakistan through Thursday.

Prime Minister Yousaf Raza Gilani met Tuesday with local and national health officials as well as United Nations agencies and other international groups to address the mounting health crisis.

The U.N. says it still needs $200 million more in aid.