Red Cross and UN officials say floods triggered by tropical storm Jeanne have killed 709 people in Haiti over the weekend.
Some 600 died in the northwestern town of Gonaives and more than 100 were killed in other parts of the Caribbean nation's north and northwest.
Authorities fear the death toll could still rise as flood waters retreat.
Earlier, Haitian interim President, Boniface Alexandre, appealed for world aid for his devastated country.
Mr Alexandre was given the floor to make his plea to dozens of assembled world leaders and ministers at the opening of the annual United Nations General Assembly session in New York.
'In the face of this tragedy, which is of the magnitude of a humanitarian disaster, I appeal urgently for the solidarity of the international community,' he declared.
Carlos Morales, the Foreign Minister of the Dominican Republic, which shares the Caribbean island of Hispaniola with Haiti, also made a call for international assistance to help relief efforts in his country, where at least 11 people died.
The storm swept the north of Haiti during the weekend, sending deadly mudslides through towns and villages. Worst hit was the coastal city of Gonaives, birthplace of Haiti's independence from France 200 years ago.
