Although Pakistan's floodwaters are beginning to recede after the country's month-long drenching, the heads of several U.N. agencies say aid still is in urgent need across the country.
The heavy rains that were so common during the past month are occurring less frequently now in Islamabad, a sign that the monsoon season might be drawing to a close.
But U.N. officials say the end to the nightmare for an estimated 17.6 million people across Pakistan who are suffering because of flooding is nowhere in sight.
U.N. Secretary-General Ban Ki-moon's special envoy for assistance to Pakistan, Jean-Maurice Ripert, spoke to reporters in Islamabad. He said that weeks into the disaster, Mr. Ban's earlier assessment that the flooding was a "slow-motion tsunami" still is accurate.
"Indeed, four weeks after the onset of this disaster, we see the wave of this tsunami still rolling through Pakistan -- destroying houses [and] lands, claiming lives on its way. And it has yet to reach the ocean," said Ripert.
Ripert said Pakistan has received assistance and pledges of more than $1 billion. But he said that is far from enough.
Speaking alongside the U.N. special envoy, the executive directors of the United Nations Children's Fund and the World Food Program appealed for more aid after touring flood-affected areas.
UNICEF's Anthony Lake said he believes that no one could have foreseen the enormity of the challenge to deliver humanitarian aid, especially after already providing two million people with clean water and immunizing hundreds of thousands of children.
"If you had told me, say six weeks ago, I would have said that we would have already been on top of the situation. But in fact, we are not." said Lake.
Lake said that six million more women and children still need clean water and sanitation.
The World Food Program's Josette Sheeran said her agency needs $90 million more to double the three million people who have received a month's supply of food.
She also said they do not have enough helicopters to reach everyone in need.
"We still find many of the roads and bridges damaged and destroyed," said Sheeran. "And so it is not necessarily making the operations easy in the areas where there is some receding or [making] planting possible."
The receding waters have allowed some people to return to their homes.
But as flooding reaches more areas in the south, U.N. officials say their agencies, along with international donors, need to adapt their strategies to help.