The United Nations on Wednesday made an urgent plea for helicopters as the death toll from weeks of massive flooding in Pakistan neared 1,600 people. “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 Program (WFP) said in a statement “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,” Prior said. The United Nations estimates that 800,000 people in need of humanitarian aid across Pakistan are accessible only by air. Over three weeks, Pakistan's floods have claimed 1,589 lives, the national disaster authority said Wednesday. The floods have affected more than 17 million people, leaving some 4 million homeless. An estimated 6 million people are in need of emergency shelter, of which just over 1 million have received tents or plastic tarps.